I think dual booting is not bad, but if you do you should really try to stay in Linux as you'll find yourself needing windows less and less as you learn how to do things in Linux. If you are going to stay with Mandrake, I'd go with 9.0 over 8.2, I found 9.0 much much better than what I used before it, Mandrake 8.1. If you are new to Linux, Redhat might be a bit harder to learn than Mandrake, but definitely not overwhelming, you can get it
right here.