I really had to search for the article that I read online...It kinda swayed me toward the 20D. Probably for the same reason I did not but the kodak DC210, 240 but the 280 (for almost 150$ more) I also (someday) will be in the market for a underwater case, I did not see as many options for the 350D... but here's that article and link if you want it in it's entirity.
From:
http://photospot2004.blogspot.com/2005/04/why-i-chose-canon-eos-20d.html
Canon Digital Rebel XT : 350D
Earlier this year, right around when I was closing in on placing my order, canon announced the next incarnation of 300D, the Canon Digital Rebel XT - 350D. And this caused a lot of dilemma! 350D or 20D ?(many folks are going through this right now... May be you too... Hmm let me get inside your head).
By all means, 350D was more like 20D's guts and brains cramped into the 300D's body and then shrunk even further. Moreover, 350D was to be sold at $500 less then 20D. So why in the world myself or anybody else would buy a 20D instead of this 350D. Well this is a completely debatable topic that can compete with Canon vs Nikon argument. There are strong reasons to buy either of these cameras. It's upto you to find out what is more appealing to you. Below is a list of what I thought about these differences.
Image size
20D : 8.2MP
350D : 8 MP
This was negligible.
Image Quality
They have different sensor, but both camera produce almost equal quality pics in identical conditions. A pro may nitpick little bit here and there. But hey, if you and me can not see the difference even at closer inspection, the difference is not there.
Build Quality
20D: Very robust, Magnesium Alloy Body with Rubber Grip.
350D: Plastic Body, no rubber grip.
First time, when I held my friend's Olympus C5060 camera in my hand, I could feel the difference between his camera and my plastic body Canon G5. C5060 felt much more robust because of it's magnesium alloy body. So I was definitely biased towards 20D with Magnesium Alloy body. Also, for someone, just wandering into dSLR world for "higher megapixel" or "better image quality" or "smarter auto modes", preferences would be still like "I still want something light and small". I was coming in from a different angle. I wanted to build a good lineup of lenses over the coming years. So whatever I get had to last few years, and had to be able to hold heavier lenses. Naturally I would go with 20D.
Weight
20D : No doubt this guy is heavy, 27.2 oz
350D : And this one is even lighter then 300D, Only 19.0 oz.
Now that is a BIG difference of weight. But again, that's what it will be if you want it robust and well built. You cannot be an 8 seater, off road vehicle and be feather weight at the same time.
Size
20D is 0.7 inch longer, 0.5 inch taller and 0.3 inch thicker then 350D. 350D is actually even smaller then 300D. For me, a person with relatively large hands, 350D felt too small for a better grip, while 20D would just fill my hands for a perfect stable grip.
Another temptation was, why not get 350D + a nice Canon lens with Image stabilization, in the same amount for which I'll get 20D with the entry level kit lens? Well, I thought, lens I can always add later on. Why compromise on camera body right now?
So I ended up choosing 20D over 350D as well. Even though the image quality differences were minimal, I selected 20D for better ergonomics and robust build quality.
Posted with permision, but relavant.
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I didn't/don't want to get "cheap"(used incredibly loosely). Am I wrong by reading into this an beleiving that the 20D is more "professional grade" and less entry level DSLR (no offense to those who have one). I mean, I can hear you already, "You paid 500$ more for a camera you don't even know how to use???" But seriously. If I bought the 20D, the entry lens the 18-55mm, and perhaps a great lense like that 70-300mm you mentioned back a page... and sat back a while... Will I be happy?
Jason