If your looking for a cool class that has some real potential to manipulate opponents to gain sneak attacks then look at Complete Warriors Invisible Blade. You must specialize in a dagger (or kukri's, which are very nice in conjunction with the keen ability or improved critical). It has full BA (5 levels) you get to feint as a FREE action in the later levels and take 10 on your bluff checks to feint (if an opponent has a high sense motive then its hard to feint but many creatures, thankfully, do not; many outsiders do though, so...). Goo relflex, poor others. You get bleeding strike (can forgo 1d6 sneak attack to give bleeding 1hp per round). You get to add some Int. bonus to your AC when your unarmored (the unarmored thing is kinda sucky so I house rule a change that turns "unfettered defense" into an insight bonus to AC lv1 +1, Lv3 +2, Lv5 +3 to AC, works against touch and flat and when your armored).
Its not that bad and its fun (its not spellcasty though). For some reason you are forced to take Far shot and Point blank shot (and weapon focus (dagger or kukri but that makes sense). You must be a 6th level rogue (although a dip in Fighter could get you there quicker, if you have a high enough Int. to get those skills).
Invisible Blade
Prerequisites: Skills: Bluff 8 ranks (can get by level 5; if you dip into fighter you must spend 2 skill points to get to 8 ranks though); Sense Motive 6 (can get by level 3, no problem).
Feats: Far shot, Point Blank Shot, Weapon Focus (dagger, punching dagger, or kukri)
Special: Must have killed a worthy opponent in one on one combat with only a dagger (or kukri, etc).
Lv. 7 (Rogue6/Invisible Blade1 OR Rogue4/Fighter1/Invisible Blade2, need high Int. to make fighter dip work); the good stuff doesn't come until later with the invisible blade though.
ABILITIES: Dex. and Int. (like normal for rogues. although con. is always good!), however Cha. helps with Bluff (although I have a house rule that lets you use Int. for bluffs which makes sense anyway)
FEATS: they must be point blank shot, far shot, and weapon focus(dagger), assuming you took no flaws and aren't a human. Later two-weapn fighting is good, so is combat expertise (for boosting that AC), and, eventually, spring attack. A good tactical feat from PH2 is shadow strike, it gives sneak attack options and a hiding after attacking boost). Flick of the wrist (complete Warrior) is awesome for starting encounters, and the rules text is quite unrestrictive (you can use it at will with no check but no more than once a round and you cant make more than one attack while doing it).
SKILLS: Bluff is a must have skill for this class (sense motive is a prereq too), sleight of hand is nice for sneak attacking on the fly (there are some good skill tricks that work off sleight of hand in Complete Scoundrel (or Adventurer i forget)) though they are not fun to keep track of), and whatever you want...
Special: Depends on if you dip into fighter or not:
Non-Fighter: BA +5, Base Saves: Fort. +2, Ref. +7, Will +2;
Skills: (9X8+int.)+(1X4+int.)
trapfinding, Evasion, uncanny dodge, trap sense +2, unfettered defense (when unarmored add an amount of Int. Mod. [if positive] to AC equal to your class levels in Invisible Blade, if you have that much Mod. of course; I replace this with Insight bonus to AC Lv1 +1, Lv3 +2, Lv 5 +3). Sneak Attack +4d6 (dagger only, +3d6 without dagger).
Fighter Dip: BA+6/+1, Base Saves: Fort.+3, Ref. +7, Will +1,
Skills: (7X8+int.)+(1X2+Int.)+(2X4+int.); with the fighter dip you get an extra feat (1st, 3rd, bonus, 6th); I suggest weapon finesse.
Special: Trapfinding, Evasion, Uncanny Dodge, Trap sense +1, Bonus Feat (must be used to get one of the prereq feats), Unfettered Defense (see above), Bleeding Wound(Ex.):If you make a successful sneak attack you can choose to sacrifice 1d6 sneak damage to inflict a bleeding wound on the foe. Every round AFTER inflicitng the bleeding wound the foe takes 1 point damage until it is healed (DC 15 heal check). Multiple bleeding wounds stack. SNEAK ATTACK: +3d6 (+2d6 without dagger).
Magic Items: 19,000gp: besides one or two good daggers (+1 maybe +2 bonus), whatever...