Everything up to the Penryns (end of 07/beginning 08) will be LGA775. It's unknown whether Penryns will use 775.
You definetly don't need 8GB RAM. 2GB is more then enough for 99% of people. You only might need more for stuff like CAD but unless you do it a lot, you'll be good with 2.
Hard to tell what to expect but probably at least 3.4 or so. 3.6 seems to be a good spot although you could probably squeeze out more especially if it's a good WC set-up.