The best printer changes about once a month as new models come out. The MINIMUM things you want to look for are:
At least 4 colors plus Black. You need the 4th color to get flesh right. Since this will be on the low end of your price range you could upgrade to 5 colors plus Black for even better color fidelity.
Individual color cartridges. U just replace what runs out. Saves $$$.
Noise level (Epson's used to be horrible). And don't fall for a demo in the store, background noise is so high it will mask the printer noise. My old epson stylus screams like a banshee during start up and when printing. My newer canon is quiet but it makes the half height filing cabinet it sits on sway back and forth as it prints.
1440 dots per inch is fine. The ink drops spread a little and that prevents graininess.
HP rolls the paper over so it gets iff'y with heavier paper stock (like top quality photo papers or card stock).
When printing photos stick with the manufacturer ink and paper. They are matched to produce the best tonal fidelity. High end photo programs like Adobe can adjust the print results for different papers and inks.
-------------------------------------------------------------------------------
Now, my personal favorite is Canon this year. I got an S820 that is great for the price (about what a new set of cartridges costs...).
If you are heavy into photography then go with a 7 ink printer.
5 colors, Black and Gray. Gray is the latest improvement it allows printing good gray scale (without it grays can end up muddy brown). These will probably be over the 100 pound limit though. Maybe 150 pounds ($200 USA I'm in the USA and estimating dollars to pounds and different import duties).
For the total fanatic there are now 11x17, 7 color ink jets for ~$300 USA.