Advantages of X58 over X48?

Is it really worth getting an X58 in winter over an X48 or P45? I know I'm building my new gaming computer in winter, so time isn't an issue...issues are ability compared to price. Here's what I'm thinking of so far (all prices and brands are approximates and cumulative suggestions). I'll take any suggestions along with answers:

-$100-200 case, many brands considered
-Intel X58 motherboard ?$
-High-end Bloomfield intel CPU $250-400
-Corsair 2gb 240pin ddr3 RAM - $160
-Radeon HD 4870x2 graphics card - $550
-soundcard, undecided if ill get one or not..comment on this?
-possibly 640gb western digital & high-end velociraptor harddrives - $380
-$50-$100, two burning dvd/cd drive

Totals up to around $1600-1700 without the motherboard. I'm hoping on brooding a beast! I'd also like to know if a good x58 will be $200 or $800, in order to consider parts financially.

your talking a completly new platform here, you cant even relate the 2. for one on avarge SOCKET B (aka neha cpu) is 33% faster then peryn for the same clock. this advantage is because of CSI and QP, then the fact its a native quad core.

simple terms, if you can wait for sept-oct, do it. if you cant then you might as well upgrade now...