I maybe biased, but to me its one of those duh  obvious choices - gotta be a Canon really.

as for 350D or 30D Id be inclined to wait if you didnt want to fork out, as the 350D is ~18 months old and well... a better model cant be that far away, surely.

but the 30D hasnt been out long, and is indeed.. a lovely bit of kit (I imagine...   cant say Ive played with one but you can be 99.9% sure its awsome.)

The 350d recently got superceded with the 400d, http://www.dpreview.com/news/0608/06082416canoneos400drebelxti.asp as this preview explains.

There are some worthy upgrades on the 400d, but for those people like me that were eyeing the 350d, soon may be a good time to buy one as surely prices will drop as retailers aim to clear them. I myself like the anti-dust and vibration features of the 400d, but as Im coming from owning a Nikon Coolpix 3100 (circa 2003), a 350d will be just the biscuit

As for the 30d, initial impressions are that its only a slight upgrade on a 20d, so if you are already a 20d owner then theres not much point upgrading unless you have a bank balance larger than Spain.

Unfortunately with the 350d, and still with the 400d, theres no spot-metering