I've been using version 2.0 of PSE for over a year. I have to agree with many others on the value/dollar. PSE (Photoshop Elements) is by far the best package for anyone (save perhaps the top-end pro digitial photographer/artist). I've been a huge Canvas fan since the early days of 3.x. I have 8.x now (and won't go to 9.x because of the direction the company moved the product) and it's got a steep learning curve but it can be used to produce the common 90% of effects on digital images. (Most of this comes from the v. 6.x - 8.x attempts to make it "behave" like PS or PSE.)
PSE 2.x introduced those ~ 90% effects with almost "point-n-click" simplicity. It did this so well that I've all but abandoned Canvas 8.x. I'm looking very forward to PSE 3.x and hope the added, advertised features make PSE the only tool I need.
I suppose the only other contender might be Graphic Converter (GC) however I can't offer any advice on this shareware program...other than to say, it probably should move to commercial-ware as it's been around long enough to be well-respected in the Mac OS community. From what I've seen of the demos, it's got the best I/E (import/export) capability but honestly anything other than the standard .jpg, .gif., .tif, .png, or .pdf file formats are useless to me.