On the 5MP being overkill:
You aren't JUST buying the camera for the 5MP and if you were, then it would be overkill. You are buying it for the quality of the picture. I have owned nearly all popular digicams up to 5MP ( I sold them for living last year). There is a clear, discernable difference between a 5MP and a 1,2, or 3 MP camera all other things being equal. You get the latest optics and the latest CCDs. If you buy for snapshots, then small and light is the way to go. If you are concerned with getting beautiful portraits and more creativity, you get a real camera.
If you think that a 5MP camera simply adds pixels to make the picture better you are missing the point and likely won't ever need a 5MP camera.
Similarly, medium and large format cameras offers a simply stunning improvement over 90% of 35mm cameras dollar for dollar. Likewise, the depth and clarity of the best 4 and 5MP cameras is simply not achievable in lower res cameras, period. If I showed you the best pics taken with a 3MP vs a 2MP of comparable quality you'd see the light. I currently own a FUJI 2800, and a Canon G1. The canon's pictures are so far superior to the fuji's that the difference in $ is worth it. To illustrate my point, I took several pics with the canon at the 2mp setting and the fuji at 2mp. The canon takes 3D like portraits while the FUJI takes snapshots. I like them both, but for different purposes.
Cameras I have used for more than 2 months (roughly 2,000 shots)
Nikon 800, 880, 885, 775, 995, 5000
Canon G1, G2, S20, A20
Olympus 2040, 3030, 4040, 3000
Kodak 4800
Fuji 2800
Minolta Diamge 5 and 7