I don't have twins yet but with my dd I used a medela double pump which worked great. But for twins I would consider renting a good one from the hospital.
I used the big medela double pump I can't remember the model name It was a rental from the WIC office
I'm planning to buy the Medela Free Style Pump. It's been recommended to me by several people. I will also look into what the hospital has to offer.
I had to express milk for my twins while they were in hospital for 10 weeks and I found the medela lactina to be the BEST. I also used a symphony which was just as good. The hospital gave these out to use while ever you had preemies in hospital.
When I returned home I used a Medela swing which was pathetic in comparison but the best on the market available to me.
I'm sure you guys know these are double pumpers (I only say this because the hospital didn't and I had to figure this out for myself after finding it ridiculous to pump one breast at a time)
I'll try and find the site but my mum also bought me a ready made bra from the internet that I could use to go hands free!! I soon learned to buy cheapo bras and cut small holes in to force the cones through and reinforced with sellotape when they got worn. Hands free pumping meant I could read, check medhelp and even cook and clean (I didn't have my babies home with me though so not sure whether you'd have time with twins at home)
Thanks guys, i've been hearing the medela is the best too. Here are two websites with the hands free bra. My co-worker got me the bra in the first link for the baby shower.