I bought one with a 20gig harddrive.
I figured it was a good deal. I spent S$380 (that's less in american) on it. I got a wireless controller, the system and a harddrive,. Not too bad, eh?
Personally, I'd just have up for one with a harddrive inclused, it's easier than going and buying it separetly, cheaper too.
'Course, the core system is cheaper, but once you go buy memory for it, it'll be the same if not more than one that comes with a drive.
I'd just save.
But it's your money.