Web page speed, youtube and Skype is dependent on your ISP speed, not your pc.
I run those applications very well on my four year old laptop, so really you don't need a fancy top of the range one.
You will probably have Vista, so go for 2gb RAM, 250gb hard drive, 15" widescreen (portable but not too small).
It is rare to get Office with a laptop, but if you need it, OpenOffice is free and compatible with Office.
Spend a bit of time at PCWorld looking and touching the laptops. Then come home and do your price research.
Don't forget Tesco has some good deals - but I can see nothing wrong with the cheap, 3gb Acer PCWorld is currently selling.
http://www.pcworld.co.uk/martprd/store/pcw_pag e.jsp?BV_SessionID=@@@@1810432799.1215079173@@ @@&BV_EngineID=ccckadeeididhdjcflgceggdhhmdfhk .0&page=Product&fm=null&sm=null&tm=null&sku=87 3891&category_oid=-35054