Spend the extra cash. The Hydrostatic Drive is worth the money. I have a Craftsman D4500 80th Anniversary edition. I spent $1400 on it last year and it's on sale again right now for the same price. 42" deck, 24 HP Briggs, hydrostatic drive. It's awesome. I've added mulching blades and a front bumper.
4500
PS. It's made by Husqvarna. Also, if you can get a Sears card, it's interest free for a year. Basically you pick the thing up, take it home, pay $120 a month for a year, and it's yours. Just make sure you pay it off by next May or they'll rape you in interest.