The Microsoft Store has launched a decent deal on an Xbox 360 S 4GB bundle. For $250, the bundle includes the 4GB system, two wireless controllers, a year of Xbox Live Gold and 4000 Microsoft Points (a.k.a. $50 worth of Xbox bucks). All of these items purchased separately would normally cost $350, so you're technically saving $100. However, we'd be remiss not to point out that if you ever want a hard drive, it'll run you another $130.
Of course, you could stave off the inevitable with a liberal dose of flash drives, or, if you're feeling particularly adventurous, you could always mod that old Xbox hard drive.