The Acer Aspire One series has become increasingly popular since it was picked up by several supermarket chains. This model makes a good entry level netbook - light to carry and easy to fit inside a briefcase or satchel on business trips.
The major pluses of the A150 are the included webcam and mic which are of good enough quality for most Skype users. The keyboard is excellent (though it might take some getting used to the size) and unlike many rival products the keys aren't of the flat 'touch pad' variety. The off the shelf hardware is more than capable of running Windows XP and Office apps as well as day to day browsing and email.
The real downside of the off the shelf model is the battery life - typically this seems to last for 90 minutes to 2 hours depending on system usage. The upgraded 9 cell batteries are fairly expensive too (around £60) and are more clunky than the machine itself. Also the lack of a CD/DVD drive may be a problem for those who dont have a large (say 8GB) USB stick to install applications from.
My recommendation would be to buy the A150 from ebay unless you can pick up one in a supermarket offer for around £130 (which is what I paid for mine) because at £250 Amazon et al are really overcharging. At the lower end of the price range these machines make nice portable media machines when plugged into a larger monitor and using USB speakers (the built in ones are frankly too tinny).
If you are tech savvy it might even be a good idea to pick up one of the earlier builds of this model which has less RAM and comes with Linux installed. I took one of these basic models, upgraded the RAM (took about 20 minutes after googling) for £20 and installed Windows 7 (which is soon to release a netbook edition) and it runs great. Those of you who don't have the inclination to take the machine apart might be better paying a bit more for one of Acer's more upmarket models (which I have noticed are now quite cheap in Tescos).
Finally be warned the screens on these can be a bit flimsy and pushing them back too far can lead to LCD cracks (though probably no more common than any other lightweight laptop) the screens are replaceable for about £50 and take 20 minutes to install.