I posted a topic about this in the Off Topic forum, "Anyone ever lease from IBM/Dell?" The basic overview of what people told me was that usually, a bank can get you a better deal on a personal loan then IMB/Dell/Gateway will give you. With some of Dell's interest rates, you'll pay $1000 in intrest with some models.
If you have a relative that works in a bank, talk to them. They can usually get loans at better rates then anyone else. Some banks even offer interest free loans to their employees for purchasing of computers and such.