Digital Rebel Xt What Lens Would I Use To Take Portrait Style Pictures With My Canon Digital Rebel XT?

What lens would I use to take portrait style pictures with my Canon Digital Rebel XT? - digital rebel xt

I'll buy a Canon Digital Rebel XT and I have no idea what lens does what. I need a goal, Sharp display size photographs (full body shots and inside) and said that would be nothing more than 5-10 feet away. If I could name the lens or something that I can do. Thank you a ton =)