I think most important is your budget ... you have two options - a netbook - or a smartphone ... if it's purely for e-mail a sm is a good option - (I hate mobiles and the people who use them intrusively - I don't have one) I use one for work - it's a cheap HTC 620 which is part of the broadband package they provide for me
I have the option of fon and other hotspots
wifi at home ... gprs out and about.
I used it for two weeks while in hospital (a lot) and was still within the allowance.
if it's a netbook - you have to consider the lack of storage as well as external inputs - the eeee range now includes a machine with dvd reader ... which is a good idea
if look on the magazine shelf at the supermarket - there have just been a couple of reviews of netbooks - it might help
http://www.expertreviews.co.uk/archiveproducts earch/9/Laptops
B rub ... I love the jobsworth crack - what would it matter if we all turned up with just a few Kg over the limit ... in fact why bother with a limit at all?
answer - not paying for your excess keeps the price of MY ticket down ... instead of stocking up - try taking less