You shouldn't have any problems running on just a SSD. Just make sure you keep all program disk and keys if you need to re install. With the falling SSD prices 240GB ones can be had for $200. You may want to go with a 249GB SSD.
The reason I didn't want to go that high, money wise, for an SSD with more room is because I feel like if I'm going to shell out in the $200 range I might as well get a 120GB SSD and pick up a 1TB Data drive for around the same price. I suppose I'm not really saving much by cutting out the $100 data drive, but for my initial purchase, since I'm on a budget, I'd rather put that $100 towards a better GPU.
I'll be sure to keep all program and disk keys safe and easily accessible whatever I choose to do, because you never know when you might need them.