I disagree strongly with these "required" magic weapons. Just get one adamantine spiked chain, and a few vials of Silversheen. DR is often not that significant, and it is not worth spending big bucks on a golf bag of weapons to be able to bypass all forms of it. If you're really worried about it, get Metalline or Shadow Striking added to your chain when you can afford it.
phaedrusxy's disagreement made me go back and look at the question of material DR in more detail. There are more than 247 core monsters in the SRD. It's hard to give an exact number because it depends on how you count certain groups of monsters like elves, true dragons, and hydras. 247 undercounts the actual number of monsters because it counts certain groups of monsters that ought to be split like demons, devils, angels, archons, and inevitables. A reasonable count is probably somewhere around 300, splitting the groups that should be and counting the dozen or so Product Identity monsters. (If you split all the monsters out, you get 587, but this is a significant overestimate because it counts true dragons of all age categories and hydras, cryohydras, and pyrohydras with different numbers of heads, among other trivial distinctions, as separate monsters.) Of those, 14 have DR/silver of some sort, 4 with DR 5, 6 with DR 10, and 4 with DR 15. 18 have DR/cold iron, 7 with DR 5, 10 with DR 10, and 1 with DR 15. In the core, only golems have DR/adamantine, 1 with DR 5, 3 with DR 10, and 1 with DR 15. (I'm counting templates with variations, like afflicted versus natural lycanthropes and vampires versus vampire spawn, twice.) Since core monsters don't have multiple types of material DR, that's about 34 total monsters with material DR, or somewhere between 12-15% of all core monsters depending on exactly which you lump and which you split.
When you do encounter those 12-15% of monsters, though, DR hammers your damage. A character with 16 Str and a spiked chain starts off dealing 9 expected damage. With a +1 weapon, a +2 Str item, and +2 Str from levels after 8th level, their damage goes up to 15. DR 5 comes in as early as CR 3, some of the example lycanthropes have DR 10/silver at CR 5, and by CR 8, all monsters with material or alignment DR from non-template sources have DR 10 or better. The core class that adds the most damage per hit, rogue, only adds 10.5 by 5th level and 17.5 by 9th level, so DR reduces their damage by somewhere between one-third and one-half. The implication is that you're better off using a non-magical cold iron or silver chain when up against material DR, and those are cheap enough you should certainly buy them. The only reason to get them enchanted is for creatures that have material DR and DR/magic in conjunction. In the core, only vampires and the three nightshades have that, and I'd feel comfortable using scrolls or a wand of
magic weapon as a backup for that.
With these numbers in mind, I'd say stick to masterwork silver and cold iron chains, but you must have those.
Silversheen is in general not a good replacement for alchemical silver compared to carrying a silver chain, since one use of
silversheen is almost as expensive as the silver chain itself, it potentially requires an action in combat, and after you've fought nine encounters with DR/silver, you could have bought a +1 silver chain for the money you spent. Metalline and shadow striking are probably out of the scope of your campaign. Compared to buying three chains of different materials, the minimum character level, assuming you're investing half your wealth by level into your weapon, metalline doesn't become better than buying three weapons until 13th level. Shadow striking doesn't become more cost-effective for material DR until 16th level, though it does work on alignment DR. I am much less comfortable using
magic weapon with a bow because DR/magic is common and a cheap wand or scroll is not likely to have a long enough duration for a slow fight because bows don't do much damage, so you'd have to learn the spell yourself when there are better choices for 1st-level spells even given the duskblade's very limited spell list, but you may want to go that way.
I don't yet have data on non-core monsters so I can't estimate frequencies there, though anecdotally I know that more different types of monsters get material DR: for instance, non-core monsters that aren't golems get DR/adamantine. Non-core monsters may or may not change this analysis.
Given another 6-8 kgp to spend, I'd buy
gauntlets of ogre power and an
amulet of health or improve your
cloak of resistance before branching out into other magic items.
What I would buy is a couple of +1 gauntlets. On one, put Smoking, and on the other put Warning. That will give you constant concealment and a +5 on initiative, both of which are well worth the money. I'd suggest adding these enchantments onto the Gauntlets of the Ghost from the MiC, which basically add the Ghost Touch property to all of your weapon and spell attacks, for only 4k.
Smoking is an overpowered, poorly-designed weapon property from an obscure Faerun-specific 3.0 supplement. For comparison, the
minor cloak of displacement takes up a slot, costs 24 kgp, and gives concealment. Smoking is obviously out of line, and no one should take it,
ever. A gauntlet of warning probably won't break the game but the whole business of taking weapon properties that were priced as if you were going to put them on your primary weapon and putting them on a secondary weapon, because WotC writers are dumb, is sleazy and questionable. If you want better initiative, go with an honest alternative like a
ring of anticipation (DU 100), which phaedrusxy and I both recommend.
I don't know where the gauntlets of the ghost are from as I can't find them in the MIC. However, there are four incorporeal monsters in the core, total, and out of 2678 monsters in the Monster Index (
https://www.wizards.com/default.asp?x=dnd/lists/monsters), only 74 are incorporeal. Incorporeal monsters are dangerous, but they're so rare that spending 4 kgp to negate the miss chance is a waste of money.
+1 Deathward Buckler/Dastana (4,375 gp)(once per day as an immediate action become immune for 1 round to negative energy and death effects)
A buckler gives a -1 penalty to attack rolls while you're wearing it, and there's no way a specialized defensive ability is worth a -1 global attack penalty. Dastanas are another obscure 3.0 setting-specific mistake that I would avoid. Other people have a much higher opinion of deathward than I do.
Belt of Battle (12k, +2 comp to Init, 3 charges for extra actions) and Health (Con +4) (16,000 gp)
You should never break the action economy unless you're aiming to disrupt the game and make your DM's life harder.
phaedrusxy's other item suggestions are good, but as I said, I would focus on getting basic numeric bonuses first.
