All the DSLRs on the market will produce the goods.
I wouldn't worry too much about the amount of pixels, I often use my 6Mp Canon 300D in preference to my Canon 30D. Take it from me you will not see any difference unless you're going to make gigantic prints
The Nikon D40 is a very good camera at £330 inc 18-55mm lens. the only problem with this camera is the limited lens availability.
Pobably the best if you want cheap, but still very good is the Pentax K100D @ £300 inc 18-55mm lens. lenses for this camera can often be picked up quite cheap on Ebay.
However if you think you may take up photography seriously (many people do) then consider biting the bullet and buying such as Canon or Nikon as there is a wealth of accessories avilable for these cameras, assuming you leave the Nikon d40 or D40X out of the equation.