Assassin 3.5e -Z

We started some evil characters awhile back and they are now level 6. I invested in *combat reflexes as a feat.

Was this a mistake? I have not been able to find any use for it per the DM's description of what can be done with it. When I selected it I was thinking it could be used to apply multiple attacks on a target, but apparently its only good for 1 attack, and if I am lucky enough for another mob to run by me that would make another attack available.

Does this sound correct? Are there any other uses, or combos w/ some other feat/spell? Also if any of you would know where I could find a 3.5e (pure DnD) guide for Assassins, I would love to read up on it. So far, other than the 1 shot ability the class feels very basic.

There isn't really an Assassin's handbook, but this Rogue Handbook has a lot of useful info.

For combat reflexes to shine you need some way to get your enemies to provoke more often. The typical method is karmic strike(CW, I think) and/or robilard's gambit (PHB2).

There's a reason that assassin feels pretty basic. It is.

Unless you have the spell compendium. The spells that get added to the list make an assassin positively shine in his role of sneak-up-and-kill-'em guy. This is why assassin is still reasonably worthwhile when all his other class features are more readily available elsewhere.

A reach weapon is the easiest method of generating AoOs, or just find some way of being large.