Sell EOS 10d or keep and get better lens(es)?

[Escapegoat]

I have a 10d that I only use indoors, on a tripod, for small product photos. I use a relatively cheap zoom lens (I forget which, but from memory, it's a slow EF, something like 35-80mm, f4 or so). After looking at the results from some of the nicer modern Fujis, I think my 10d results are a little soft. And sometimes, I'd like to go closer for detail than the zoom allows.

Being in Japan at the moment, I can scour the used shops in Tokyo for nice fast lenses for the 10d, or - if the experts here think that the 10d's 6MP sensor is a limiting factor, I can perhaps look for a replacement camera.

Thoughts?

[Escapegoat]

Thanks for the advice. I'll see if I can find the 100mm macro lens here. The L-series goes for big money and doesn't seem to provide me with much extra benefit.

Not sure if the same is true of USM, but it doesn't look to cost much more than the original non-USM version and would be easier to sell on if I did decide to go to another system.