RH 6.1 Server install will blow everything away
There are at least a couple of options I would recommend. The Server installation option of the Red Hat distribution will set up your entire hard drive -- in fact all available hard drives (be careful if you have more than one and you'd like to keep whatever is on it) with a server installation. If you wish to learn about RH as a server OS this might be a good option. You should probably have a hard drive with at least 1.6 Gb.
Another option would be to use choose Workstation and setup two partitions on your whole drive: root and a swap. This is the easiest configuration to manage for a new user since you don't need to know how much space your files will require on the individual partitions. For a mostly complete workstation install you might get by with a little less than the server. In either case, I wouldn't let this concern you unless your hard drive is smaller than 1 Gb.
RH 6.1 install is pretty straight forward - well at least the getting-the-software-on-your-hard-drive part. After that, the learning starts. B) However, since you don't really care about what's on the harddrive already, you can afford to be a little bit more adventuresome. So go for it!
(BTW - if you're hoping that you'll be up and running the way you were on your previous OS - such as Windoze, before the week is through, I'd think twice about blowing it away! That's my $0.02 and then some.)