kcbrown wrote in post #3891356
Ultimately it's going to depend on what you're trying to do.
If there's a focal length range that isn't covered by your gear that you really need to cover, then a lens covering that range might be worth it, depending on how often you expect to need to shoot in that range.
20Ds seem to be going for about $600 these days, with 30Ds going for around $800 or so. Many 30D owners have upgraded to the 40D so the price on those has dropped a bit.
Unless I were going to use the new focal length range a lot, I would upgrade the body. While it might not necessarily help your images all that much, I expect it will significantly improve the shooting experience. I don't know about you, but one of the big reasons I enjoy photography is the feel of handling the gear. If that weren't a significant factor, I could get away with just a point'n'shoot or something (though I wouldn't have nearly as much control over the results).
Dekka wrote in post #3891966
Just asking this question implies you are content with the performance of your Rebel. Am I wrong in that? If I'm not, go with glass. When you tire of your 300D, the good glass you invested in now will still be there and you'll have had plenty of good use out of that body in the mean time. And possibly, by that time, there'll be a bigger and better and cheaper body than what's available today.
$1200 gets you into some worldclass glass.
If the camera's holding you back, and it sounds like its higher-ISO performance is hurting, then a body's a reasonable option. Going even to a used 20D will get you better high ISO performance and better AF performance as well. Going the used route will leave you some left over to upgrade one of your lenses, or to fill a gap in your collection. You could, for instance, replace the kit 18-55 with a faster 17050 f/2.8 from Sigma or Tamron, or get the 70-200 f/4 (non-IS) L, or a 10-20 Sigma in addition to a used 20D or maybe 30D.