I bought a used Canon digital rebel / 300d back in 2006 with a Sigma 18-50 1:3.5-5.6 DC and a Sigma 55-200 1:4-5.6 DC. They've been through a lot and still work fine but lately I've felt pretty uninspired and feel it's about time for an upgrade.

Now I know that generally you're better off spending money on lenses than on the body but quite a bit must have happened since the 300d came. New semi-pros are a bit too pricey for me given my level of interest (hobby/creative outlet sort of use..) but I've seen there are some quite affordable second hand 40D:s on the market and that people still seem to think it's a good camera. Does that seem like a good alternative? (Fx saw one today in good condition with a Sigma 17-70mm F2.8-4.5 DC MACRO with some extra stuff for 4200 sek/~$600). Or would I be better off putting a better lens on my (really) old camera (keeping in mind that I couldn't afford anything top end)?

grateful for any advice!