Hi there fellow WordPressers...
I've had this problem with thumbnails for months and just about getting there, here's my site (using the theme Autofocus, heavily modified).
I'm using TDO Mini Forms to allow users to submit posts, which I then would like a thumbnail generated on the homepage. I've been through every thumbnail plugin known to man and most of them seem to be stretching my thumbs on the homepage even WordPresses in built thumb feature is stretching them too. At the moment I'm using the plugin 'Ordered Thumbnails'.
Is this something to do with the theme, and am I missing something totally stupid. I've set my thumbnails size in the media settings to 250 wide x 170 height, I've also tried endless other combinations.