You don't generally have to use their email domains, and if you want a differnt homepage just change it in IE.
I'd suggest your first priorities should be reliability and price, as these are probably the most important factor for most people (and FUP/download allownaces if you're going to be downloading a lot).
Any Enta reseller seems a good bet right now, and perosnally I would NOT touch AOL / Tiscali / Fast4.
If you have a contract o2 phone you might want to have a look at them - I think it is still £7.50/month if you have a phone with them, and it will be goiing up to 12.50 soon (end of March I think) for new customers (but the £7.50 cost is permanet if you sign up in time, I think).
Alternatively, if you want to download a lot, and you can get it, Be is worth a look. You don't get any webspace or emails (I think both are additional cost extras) but you do get fast download speeds.