Right now I'm a light side pure halfling dex dragonmarked lvl 12, and pretty happy with it, but the new prestige classes sound pretty good particularly the ninja. It would be a radical change, so I don't think I could do it with just feat and enhancement respec probably need LR.

I'm thinking of taking Rogue at first level. The main reason is sneak attack damage. I'll usually be sneak attacking, whether because someone else in the group has aggro or unbalancing strike. An extra 1d6 +3 damage per attack, with the number of attacks monks get, is Huge. The other major reason is UMD. I'm not looking to no-fail res scrolls, but it would be nice to use rr gear, lower level wands and such. I won't bother with trap skills - no way I could get them high enough with only 1 level of rogue and dumping INT. Proficiency with short swords, with them being made ki weapons is another situational bonus from rogue. At lvl 20, if I really want the cap I could LR again into pure monk.

Another choice is animal path. I have monkey now, and have been really happy with it. However, as a dark monk I'll have much more need for ki for ToD (and QP in another level or two), so I might switch to Crane. Also related to ki generation, I think up until maybe grandmaster wind I'll be better off using fire stance + haste potions. The nearly doubled ki generation should more than make up for slightly lower attack speed. It doesn't seem to make much difference using the starter fire stance vs. master fire stance (1 point of strength isn't worth the enhancement points, and by grandmaster I'd switch to wind anyway). I'm leaning towards keeping monkey path but switching to mainly fire stance if I'm going to have haste, but I could use some input.

For feats, that's the main problem with my current build. Full dragonmarks and finesse means no stunning fist or improved critical yet. I think I'll change to STR based and drop the dragonmarks. If I have an extra feat or so, perhaps an additional toughness.

Hard to know without seeing what teir two of the prestige classes bring, but those are my current thoughts. Feedback would be appreciated.