Alternative to 18-55mm kit lens?

I'm thinking of upgrading the kit lens to something a bit better but not massively expensive, say £300, pref new or through a dealer with warranty if secondhand.

So what do people suggest? (other than spend more!)

The Tamron 17-50mm is a good choice if sharpness is your thing.

The MkII and WR versions of the kit lens are really pretty good, but the next step up would be the 16-45mm f4 or the 16-50mm f2.8 or the 17-70mm f4. The 18-135mm WR is a useful choice but probably more on a par with the kit lens for quality.

SRS have the Tamron 17-50 for £299, although I have seen it elsewhere at various times for less than £250

Gets great reviews for image quality. Not so great build apparently. SRS advertise it with a 5 year warranty though.

Or you could take a gamble. There have been a couple of 16-45's on sale here privately. One Pentax and one under the Samsung label. That one is £160

I'd go for the Tamron 17-50 preferably non VC. Used one on my D40/D7k (for the few weeks that I had it) and it was a really amazing lens for the 290 I paid for it. Build quality and AF speed are a bit lacking but both adequate given the price.

Sigma also has a new 17-50 out which sounds like a good alternative especially if fast focusing is a priority for you (I had the 50-150 HSM I on my Nikon and the AF was so fast it makes my 50-135 cry). It does cost an extra 150£ or so from the Tamron.

S/H 16-45 f/4 is your other option if you are on a budget and you don't much care about the slower aperture - as pointed above you can get them for as little as £160 and doubt you will lose out much if you don't get on and end up selling it on.

Cheers guys, I'll have a look at that lot, particularly the tamron.