I3 vs I5 for home office computer

If you're doing the basics of web browsing, office documents and videos then the i3 is more than enough. The only reason you'd really want the i5 over the i3 is if you were going to play games at high settings.

Yeah, for simple office tasks the i3 will be more than enough.

While a program like Excel can make use of a quad core CPU, there will be no noticeable performance increase unless you are doing some complex financial or scientific modelling. If that's the case, then I recommend waiting for Ivy Bridge since those two tasks uses AVX instruction sets and IB's upgraded AVX instruction set is estimated to give up to a 30% increase in performance for financial and scientific modelling.

would that 30% be included in the new I3 processors too or just the quad core I5 and I7 Ivy Bridges? Also is the release date still set at April 29th or sooner?

The updated AVX instruction set applies to all Ivy Bridge CPUs. Just be aware that AVX (Advanced Vector Extensions) have very limited and specific uses. If you're not doing financial or scientific calculations that takes advantage of the updated AVX instruction set, then you will not see much improvement over Sandy Bridge CPUs other than the difference in clockspeed and the potential increase in Ivy Bridge's IPC (instruction per cycle).

Buy the i3, and use the saved money on an SSD.

I agree with jaguarskx. For Microsoft Office, CPU really doesn't matter unless you are doing heavy Excel or Access work. I do a lot with Word 2007 (working with 300+ page files at least an hour a day), and I can't tell the difference between a brand new i5-2500K (some times work at my buddy's house who's a gamer), and my old Pentium E2200 desktop and my old Core2Duo laptop.

My thought is if this is an office machine, I personally would go with an AMD Llano. That way, I know I got a decent video card for light gaming and such.

Thats what I was thinking of doing.