There's a couple of other things as well that differentiate the two:
1. Can't select the AF mode (Single Shot, AI Focus, AI Servo) camera chooses for you --> maybe a big deal, maybe not. I do change the setting on my D60 depending on the circumstance.
2. No rear dial, so some controls will be harder to set (10D exposure settings are on buttons / wheel, 300d is in menus)
4. No mirror lockup --> again, not a big deal UW, but definitely topside for long exposures
5. Lower ISO (1600 max vs 3200) --> probably not an issue UW
6. Pentamirror vs pentaprism for viewfinder (darker viewfinder) --> have to see how it behaves
7. Higher crop in viewfinder (.8X vs .88X I think I saw somewhere) --> definitely something I'd have an issue with UW as well as topside. I already complain about the D60 because of the .88X, so losing another 8% of the frame would be aggravating
8. No custom functions supposedly --> Could probably live with this
9. Top LCD is gone, actually looks like it's shrunken and put on the back, maybe not backlit.
10. New "short focus" mirror assembly to accomodate the new lens that Craig mentioned. Potentially longer shutter blackout than a 10d
11. Crappy silver body instead of ultra cool black 
Ok, so based on that, would you buy the 300D? I'd have to say that it'd be a tough decision right now. Looking at it from a purely UW point of view, probably not a bad choice to pick this and put the extra $$$ towards a nice lens. I don't think that I'd want it to be my only camera topside though. As for "side-grading" from a D60, I won't do it, even with the improved AF and DIGIC sensor. But then again, I didn't upgrade to a 10D either, because it wasn't enough of an upgrade. I'd like the better AF, but it's just not worth it.
NOW, with this, the street price of the 10D may come down, and this will certainly push the price of a used D60 down, which might be compelling.
Herb, please don't buy one of these, the images I've seen you produce with a prosumer cam are amazing enough. Can't imagine if you had an SLR and some high quality glass! 

