there is slight increase in writing speed due to the DIGIC II processor (4x faster than the S1/A95/A80 DIGIC I processor). However, due to shutter lag inherent in any P&S, you'll be hard pressed to feel the difference (you'll see the difference, but you won't really feel it).
For browsing, it makes a LOT of difference. (but then again, how often do you browse?)
The REAL main advantage is when you're downloading to the PC.
For my photo session, sometimes I can take up to 2 Gb of data. It makes a lot of difference downloading 2 Gb of data at 10 Mbps vs 2.5 Mpbs)
Conclusion: if you don't mind slower download time, you're not going to take video ever, you don't browse too often, forget about the Ultra II and get the regular version. It's cheaper.