I'm in my mid to late 20's, have lived in Bangkok before (albeit many years ago when I was a sprightly 18 year old) and have travelled there on a few occasions since. I currently live in Shanghai. Last time I went I was ill-prepared and consequently ended up in a few terrible bars and restaurants (Kao San Road etc etc). What I'm looking for are bars with some decent electronic/eclectic music, a nice mix of locals and expats and, most importantly, somewhere to meet some nice, pretty girls who aren't likely to turn out to be prostitutes. Do such places exist? To give you some idea of my tastes, last time I enjoyed the Sky Bar near the Oriental Hotel and Bed Supperclub. Any more places currently busy, fashionable and along similar lines?
As for restaurants, any decent roads/areas for good Italian and French food/wine? Also, any personal recommendations for the best gastonomic experience in BK?
Might I suggest you go back to the bars that you have previous experience with, and when you meet people of your caliber, you ask them for where to go.
NOW, you can also check out the bangkok guide as that gives restaurant recommendations and clubbing info.
I can tell you what bars have expats in them, but I can't tell you if you will be able to hook up with any girls and / if, they are prostitutes or not.
you can still go back to sky bar / bed supper club. slim at RCA is still quite popular. check out guru magazines that comes with bangkok post every friday. or pickup BK magazine, both gives a pretty good idea what's in n what's out.