Wheels & Tires

I have a 05 Silverado LS 2x4 Crew Cab.  I want to get some aggressive rims and tires for it but I dont know where to begin to look.  I live in Irvine CA (Orange County).  I'm looking for 18" wheels (Black) with some big tires to match.  I plan to lift the truck a little but I dont know how much is necessary.  My goal is to basically give my truck that aggressive look and not necessarily an "I can run over anything appearance." 

Any suggestions would be greatly appreciated.

RQ 05 LS 150038523.6765509259

try out tirerack.com and discounttire.com  you can even see what they will look like on your truck