zuchri

well, FYI Mashable is using wordpress, it's good for fast paced sites, forum function in wordpress can be added with bbpress, there is even social layer extension called buddy press, eventually it depends on your need

stick with forums like this, read blogs like smashing magz and learn from the showcases featured, using softwares like dreamweaver may help, but eventually hand coding is the best approach, good luck

liquid layouting will do the job, but indeed keep in mind that >70% users are now on screen with 1024x768 higher, using multiple stylesheet would also be a good idea, since now many devices available

Well, what would you need?

swish would be good for beginner

simply saying, try balsamiq :)