Its just one of those things you start to pick up on when you become critical of your own work.
I am by no means a professional photographer, and tbh I wouldnt even say I am that good, but I know what makes a good photo!
If you want to have a look a lot of my 'serious' photography is showcased on http://stumac1985.deviantart.com its not up to date though as I am working on my own website currently.
I just bought a Olympus E510 recently. I read pretty much ALL reviews on entry level DSLR's... it had the best features and got the best reviews.
Can be picked up from Dixons with 2 lens 14-42mm and 40-150mm for only £399.
Its one of the only DSLR's to have Liveview, Image Stablisation and an Anti dust feature. You only get these when you start spending £800+ with other cameras.