System Temps -- Should I be Worried?

I built my system about a year and a half ago (Feb. 2007) and haven't had any real problems. But I downloaded Speedfan and some of it's readings have me a bit worried. The northbridge is consistently around 64C and the video card consistently around 54C (unfortunately the very end of the video card hangs over the northbride heatsink), the rest of the temps are fine. Is this something I should be worried about? The northbridge has a heatsink and fan, but should I consider buying a new cooler to try and lower the temp a bit?

Here are some specs, let me know if you need any more information:
Mobo: Gigabyte GA-M55-SLI-S4 rev. 2.0
PSU: XLCIO GOODPOWER 500W
Video Card: GeForce 7600 GS (256mb GDDR2 pci-e x16)
CPU: AMD Athlon 64 X2 3800+ (2.0GHz dual core)
Memory: 3GB

Thanks a lot for any help.

Hmmm. Thanks for the reply. While I respect your opinion and am grateful for it, I'm still worried . During full load it can get as high as 74C, and the tail of the video card hangs over the heatsink. Yesterday I noticed that the fan on the video card had failed (I guess the bearing died; the fan was stuck and grinded and rocked on the axle if I tried to turn it manually). So I am RMA'ing the video card and have ordered a new one with better cooling, but I'm still worried that the northbridge will not only shorten it's own lifespan but that of the video card as well. I have ordered 4 new case fans (2 120 mm and 2 80 mm) to replace the crappy ones I have now, so hopefully that will help out. But just in case, does anyone know where I could purchase a high-quality but low-profile north bridge fan? As I mentioned before, the tail of the video card hangs over the north bridge, so the cooling unit can't be taller than half an inch or so.