The problem with the benchmarks you supplied (from notebookcheck.net) is that they are composites. You can look at individual details for some of the benchmarks (click the + next to xx Benchmarks and Specifications), notice that the 13" 2010 is one of the systems in the 320M results
here. They are running on very old driver versions, and it appears that the MacBook Air has double the performance (the SSD maybe?).
Now look at the Intel results
here. Using the same method, you can see that (for example), the 3dMark06 is being run on 2500K, 2600K, 2820QM and 2720QM, which are is 2 i7 quad core mobile CPUs, an i5 at 3+ Ghz and an i7 at 3+ Ghz, so, of course, the benchmark is going to appear much faster.
The intel results do not give an impression of how the HD graphics will perform in a MacBook 13" and I suspect it will be considerably worse than the notebookcheck.net benchmarks show.
I was looking at getting either the i5 or the 2.66 C2D 13" - in the end I went for the 2.66 Ghz C2D/320M on refurb - the intel seems to have roughly the same or worse performance, and at a price premium of 20% extra for the i5, it wasn't worth it for me.
Lets hope it's enough faster than my uMB when it arrives - hopefully I can play starcraft 2 without boot camp now