VoP tends to flop on it's face. You get basic six (deflection/natural/armor/shield enhance, weapon, ability boost) at lower scale than what you could buy and your alternative bonus, like VoP's Deathblock & Freedom of Movement, are rudimentary and obtained slower than normal. Plus you totally give up utility based items such say even being able to use a Passwall scroll to walk under an army to assassinate the king. No Maneuver granting items, no Wands of Hunter's Eye, etc. Now VoP isn't entirely un-feasible. Strictly speaking Grafts, Magical Locations, and Spellcasting Services do not break your vow as they are not magical items. You *could* build something useful out of it but we're talking a high level of optimization and your DM will probably prevent you from using those anyway.
Personally, I'd pick up Spellcasting and either create your own items or buff up with spells. Ascetic Monk / Sorcerer / <Something> Fist has a very nice Monk-like feel while picking up spellcasting. Alternatively there is always the Unarmed Swordsage which deserves a mention whenever someone mentions Monk. But assuming you want Monk and Monk only; I consider Passive Way the greatest none-Dragon variant. But don't forget your other ACFs, they fix the otherwise unusable Class.
Passive Way Monk 1: Improved Natural AttackFlaw, Combat ExpertiseBonus, Skill Focus(bluff)Flaw, Battle Jump1st.
Passive Way Monk 2: Improved TripBonus, trade Evasion for Invisibility (immediate action, lasts 1 round, usable once per 3 rounds).
Passive Way Monk 3: Unknown (or skill focus)3rd, Trade Still Mind for Prayerful Meditation (bonus on all spell effects if opponent's alignment is opposite)
Passive Way Monk 4: Trade Ki Strike(magic) for Holy Strike (+1d6 vs none-aligned), trade Slow Fall 20ft for Wall Walker (can run on walls).
Passive Way Monk 5: Trade Purity of Body for Resistant Body (resist [one element] 5).
Passive Way Monk 6: Knock-Down6th, Trade Bonus Feat for Track, gain Survival as a Class Skill and dump your points in it.
Passive Way Monk 7: Trade Wholeness of Body for Shadow Blend (total-concealment if not in full-daylight).
Passive Way Monk 8: Nothing to see here, move along.
Passive Way Monk 9: Snap Kick9th, Trade Improved Evasion for Blink (immediate action, lasts 1 round, usable once per 3-WisMod rounds, 16 wisdom means indefinite usage).
What you have an a totally concealed Monk that deals double damage on a charge (battle jump), and after hitting with his attack gets a free attempt to Trip (knockdown), with a +12 Bonus before other factors (im-trip/battle jump/passive way). When your opponent provokes an AoO for standing you Snap Kick them and attack twice. Thanks to ACFs/Concealment, you have +2 to attack, +1d6 damage, and roll against their Flat-Footed (no dex bonus) AC. The 3rd level Feat is best adjusted to what you want to PrC out to. Shiba Protector's adds your WisMod as a bonus to Attack/Damage rolls (adds, not replaces, str&wis) and you'll need Alertness as your 3rd level Feat and to pick up Iron Will using a Otyugh Hole. Alternatively you can pick up Combat Expertise in the 3rd level slot and take Robilar's Gambit to really penalize anyone that tries to attack you.
You have a lot of options when it comes to PrCs, but honestly sticking around in Monk long enough to pick up Shadow Blend is worth it.