Dan, the 350D provides very good results, but is now an old device and is being consigned to the grave by Canon as things are moving on and you would get more bang per buck, by going to the 400D. Like the 300/350D, it is physically small and I urge you to wander off somewhere where you can handle it and see if it suits you. For comparison, compare it maybe with a Nikon D80 and just chuck them both hand to hand and see which feels the more intuitive and is the best fit for your hands. If the D80 wins and sadly, I think it might - then you could either hang on, because Canon have to have an EOS30D replacement in the wings, (larger, heavier and more robust) or see how much the dealer might give you for your existing Canon kit. If that is more than you think, then you have yet more options. I would urge you to do a comparison though. When you are shooting, all of that brainspace can be used for interpretation of your subject, rather than trying to remember how to fiddle it into another mode or what have you.
HD, I post process all the way. I actually enjoy it too and it allows me to rescue the odd minger that would definitely be as dead as a Dodo, were I shooting JPGs. Oddly, I find it therapeutic in another way too. Because I am intimately familiar with the charateristics of each shot, as a by product - and not a necessary one either - I have relearned much about photography, but in a homeopathic way, rather than the often dry as dust method of reading it all up. I think it can help you become as one with your camera, which just leaves me the old problem of why I keep getting shots of just one eyeball.
New lens yesterday. This is a great and fun way to become bankrupt. A 10-20mm Sigma wide angle which on its few test shots to date has given amazing sharpness and some dizzying perspectives that were previously denied me. In Film SLR terms, this is equivalent to a 15-30mm and it really does make your mind fizz. Absolutely no use for aviation at all, unless you have the nose pitot shoved up your left nostril when you shoot, but a great way of adding to and rounding out your kit from the opposite end.
Conan