I just looked up what it would cost me to upgrade to the lowest i7 platform. Almost had a heart attack.
i7 920 retail: 304.99
ASUS P6T Deluxe: 338.99 (I trust ASUS more than MSI,Gigabyte, etc. always have used ASUS)
6GB kit (3x2GB) G.Skill DDR3 1600: 279.99
Total: 923.97.
So the most noticable difference you will perceive, OP, is a much lighter wallet/bank account. IMHO.
Holy Schnikees.
I remember upgrading to C2D e6420 and 2GB ram with ASUS P5N-E SLI cost me about 550.00.
I hope i7 prices come down a peg or three and the motherboards that support them, very soon. Not to mention the still insane prices of DDR3. So, while I would want to upgrade to the latest platform, looking at my current system: Q6600, 790i, 2GB DDR3, I don't think I'll have any trouble waiting for these prices to come down. The only thing I could see myself doing is getting another 2x1GB kit of DDR3 for it. I could use 3 of the 4 sticks for i7 so I could at least have 3GB in TRI for it.
All I'm saying is, I hope AMD lays a hurting on Intel with Deneb/Shanghai pricing. It should force Intel prices down, I would hope.
Sorry for the rant, but my god it's getting expensive to own a new intel platform. Even the lowest end offered at the moment.