I don't know what problems you had with Acer, but I have an Acer PC that has given excelent service over the last three years without a glitch. You may have just had a 'friday bad one'.
Check out some of the offers in PC World and the like. The shops reputaion is a little tarnished by the lack of customer support but the gear they sell is fine. Check if it is cheaper to order on line and collect at store, because that can save you as much as 15% off the price. Your statutary rights are not effected by 'collect in store' sales, but if you ever have a problem with anything purchased at any of these type of stores, just read up on your rights under the Sale of Goods act and don't take any nonsense from them.
For student use, they will be as well off with any laptop that is fron a good name and with at least Windows 7 Home Premium as an operating system.
They will require a decent Office program so why not get
Microsoft Office 2007 Home and Student Edition (3 User Licence) (PC), it will cover installation on both laptops, and your own computer as well.
DO NOT be sold the extra warranty/guarantee or what ever they want to call it.
Under the Sale of Goods Act, any thing you purchase is not just covered by the one year guarantee but it should be of usable quality for 'upto' 6 years depending upon the value and the expected usage of the product. So a laptop should be covered for about three years at least.