I would love to say that they are cheap and junky, but that is far from the truth. Most DSLRs are good value but many will not be suited to astrophotography.
I think you would be happy with the 350D!
I own a far superior Pentax (I wished I had a 20Da) but there are times it has its limits.
A couple of pics i took with the 350D, i love it and have seen some awsome astro pics taken with it, see Chris V's M42 in the mount for sale thread, taken with a 300D.
I don't have tracking yet, or a scope, so i can't take any of the deep stuff yet, these are all tripod mounted with cable release, click and hope for the best, apart from the moon that was taken afocally through the dob.
Gotta say the Canon is so far in front of the pentax and way more superior
The difference between the Nikon, Canon and Pentax isn't all that great, they will all give very good results. Canon DSLR's have the best noise performance and that is a plus for Astrophotography. The 350D is also 8Mp (as against 6 Mp of the Pentax and Nikon) and the extra resolution is useful, especially when cropping images. The 8Mp E300 Olympus reportedly doesn't perform as well at high ISO's as the other DSLR's.
The 350D has many of the features that the 300D had disabled in their firmware, like mirror lockup. Although 6mp to 8mp wont be "that" noticable, the features are nice to have without hacking into the firmware. The camera is lighter and smaller than the 300d, but it's bigger than my current s7000 so wont notice the size difference. It also has USB2 which the 300d doesn't. As far as I am aware any control the 300d has on the computer can be put onto the 350d.
The 350D is a great Astrophotography Camera. Its the best bang for buck right now and replaces the 300D that used to have that titile. best Thing about it is the USB2.0. RAW images download to PC in about 4 seconds. JPGS even quicker. Ths makes remote control of the camera fro eclipse photography a dream.....
The Canon DSLR's are by far the leading DSLR for Astrophotography. They have lowest noise sensors, more accessories and more software support than any other camera. (sorry Nikon, Pentax oweners etc...) but its just the facts....
There is not much need to go to its big brother the 20D. Next step up would be the 20Da but its hard to get in Aus and very pricey in comparison.
I'll admid the 350D and 20Da are much better cameras, but when I bought mine the price difference between the 300D and the Pentax *istDS was nearly $600, a no brainer for me because I wanted a general purpose camera. My next purchase will be the 20Da unless Pentax come up with a Canon beater in the meantime.
I use the 350D(unmodified) for DSO's. I guess you've read all the reviews on it by now, so no need for me to brag on about how good it is
I'm very new to astrophotography, only got my 1st telescope in May this year and i have produced images that i'm happy with with this camera...
keeping in mind that i have very limited image acquisition and processing skills and i have not started using darks and flats yet , have a look at my DSO gallery on my website for images taken with the 350D.