Well, my 2 GB of G-Skill RAM arrived today from newegg (superfast delivery, do not pay for rush shipping). After I installed it, it seemed my new blackbook was running much hotter than usual. So I decided to run my own (extremely non-scientific) test using istat. The results are as follows:

1GB:

Boot time: 24 Seconds
Time to open itunes: 6.65 sec.
Time to open Garage Band: 7.84 sec.
Time to open iphoto: 1.8 sec.

Temps in deg. F @ Startup; after 10 min.; after 20 min.:

CPUA: 103 115 128
Heat Sink A: 92 108 117
Heat Sink B: 92 106 115
Enclosure Bottom: 79 83 86
Mem Bank A1: 83 97 103
Battery Life %: 100 94 91

2GB:

Boot Time: 24 Sec.
Time to open itunes: 6.22 sec.
Time to open Garage Band: 7.84 sec.
Time to open iphoto: Too short to time

Temps in deg. F @ Startup; after 10 min.; after 20 min.:

CPUA: 104 128 128
Heat Sink A: 92 119 121
Heat Sink B: 95 117 119
Enclosure Bottom: 77 88 88
Mem Bank A1: 83 108 112
Battery Life %: 100 94 90

Most of the time during both tests was spent surfing in Safari to keep the computer from sleeping, so the CPU wasn't being overly taxed.

Conclusion: It would seem that doubling the RAM makes the applications somewhat faster, with very little tradeoff in increased heat. The fan speed stayed at a steady 1800 rpm through both runs, and after over 50 minutes running with the 2 Gigs in the temps remain at the 20 min levels - except for the Enclosure Bottom which is up to 95 deg (warm, but not hot enough to burn).

Hope this helps those considering a RAM upgrade for their Macbook.