I'll start with a caveat: I'm as inexperienced as they get in build planning.
That said, I'm rolling up a dex-based Helf assassin rogue (just because) and would appreciate some input on what dilettante feat to select. I was first thinking about taking Fighter for the martial weapon access, but I don't see that being very useful at end game where assassins usually rely on vorpal strikes, and weapon proficiency isn't as important. I also thought about taking Wizard, but it seems that there isn't much to Wizard dilettante that a good UMD number doesn't also take care of. Same for UMD and Ranger, plus I won't be ranging so the +2 ranged damage doesn't sound appealing.
Any advice on what I should take, or information on benefits I'm missing for taking one feat or the other? Is there a huge damage increase for a martial weapon that overshadows finessed rapiers? Are there wands/scrolls I'm not thinking of that can't be used normally without Wiz/Ranger dilettante feats?