The 1.3 SMC update has an unclear effect on temperatures. (It brings me up to version 1.27f2 - go figure.) I was running up to 83C or slightly higher according to iStat, under moderate to heavy load. (The load was an external monitor streaming Netflix, Wi-Fi running at 150 KBps, and several applications. This does not seem like a heavy load to me, but I guess decoding a movie takes work.)
Tonight, I went up to 83 without even any streaming (but with an external monitor). But after a few minutes it has settled down to between 72 and 76.
Here's my complete temperature list for comparison. First number is first reading; second is 10 minutes after startup.
CPU A 82 / 71
Airport Card 51 /52
Battery 30 / 30
Enclosure Bottom 33 / 34
GPU Diode 82 / 79
GPU Heatsink 68 / 65
Heatsink A 62 /61
Heatsink B 46 /45
Memory Controller 52 /51
Hitachi Drive 21 /21