The 18-55 VR is actually very underrated IMO. I certainly don't think it's IQ can be criticised in any way. I have seen a number of reviews suggesting that it may be better than the 18-70 and 18-105 kit lenses purely in terms of IQ. That said, it is let down by being a little toy like in construction (particularly the focus ring) and also having a rotating front element which makes using filters a pain. It's still a decent thing to start with though. The 18-105 is more versatile and overall a better lens but I wouldn't pay a fortune extra for it.
If you can get a good deal on body only, then as above the Tamron 17-50 2.8 (or the Sigma 18-50 2.8 that I use) is sharper, faster and available for £2-300, just make sure it's the one without VC.
For a telephoto, the Tamron 70-300 isn't bad for the money. It's great value but there is a certain element of 'get what you pay for' particularly in terms of build and sharpness at the long end especially wide open. I swapped mine for a Nikon 70-300 VR and its only now that I notice the limitations of the Tamron. If you can afford the Nikon, it's worth paying the extra. If you can't the Tamron isn't a bad option at all. There is always something better and more expensive in this hobby! The other good one is the Nikon 55-200 that others mention. Bit of a bargain too and it has VR which the Tamron doesn't.