i use a medela symphony, which is great - very quiet and gentle, but effective. i think you would have to hire one though - they are over £1000 to buy!!! mine is from a breastfeeding support service attached to my local healthcare trust, so i am very lucky to have it.
the most important thing i think is that you need a good, electric double pump otherwise you will spend your whole life attached to the pump!
just wondering, why are you thinking of expressing? to be honest i wouldn't recommend it if you have a choice, but if it's the only option for you, then i wish you luck x