advice on your 1st build? take time, absorb all the info possible and double check everything. tbh I'd actually start messing with that dell as much as possible now. they are by no means the pinacle of hardware, but ripping it open and looking at some basic's can only help.
my preference for Intel chips right now.... Gigabyte, DFI, Asus; there's a couple more manufactorers, but those are my top 3 as of this moment.
What do you need, how much do you want to spend? Can you use ant parts from your previous system? I have the P5N32-E SLI motherboard and I love it, it's not the most expensive but it's solid, stable, and overclocks great.