Hi James,
I made a similar purchase like yours a few years back. It was a toss up between a DSLR and a Bridge cam with masses of zoom. I ended up buying an Olympus C770 UZ as it had great bang for buck.
It took great pics up to A4 size without any pixelation problems around ISO 400. If there was ever any problems with the pictures or the camera I used to do the old master reset option and that fixed everything. Have you given that a try?
With respect to DSLR, find a model that you like and see what features it offers and then look at the next model or 2 above it and see what they offer. Go and ask people about the different features and what they do and what advantages they will give you. I purchased a Nikon 40x a year ago and it was a great camera. I didn't know much about photography when I bought it and it suited my needs. I then did some research and learnt more and did a few courses and found that it lacked some features that I needed like, Bracketing, Depth of field Preview, a greater range of ISO selection to name a few.
Not long after discovering these new features I upgraded to the D90. I make a point of looking for a camera that has features I want now and that has features I will probably grow into and use in the future. With respect to what make to buy its all about personal preference. Try a heap out and see which one's you like
Just remember to choose a manufacturer that you will buy your next camera off has a model that you would like to upgrade in the future. Means you can use all your previous gear with you new camera.
Its a bit of a ramble but I hope it helped.