I'm on BT's fibre optic service with a 37mbps dw, and 8.1mbps upload which is lightning fast when playing gt5 =) anyway, using a 2/3 mbps line would be "ok" but might stuggle a little at peak times, so i'd advice either changing to BT or Virgin, as theyre more reliable at peak times and plus BT's new BTHub 3 performs much better than any other ISP in the uk
I've just switched to TT, i was with BT and after BT i switched to SKY. SKY is the absolute worst for Broadband, BT is not far behind SKY,i've had TT for just over a month now, i get better D/L speeds and GT5 seasonals are no problem, nice and smooth...but it also depends on how far you live from your nearest telephone exchange, and also what the wiring is like in your home and if you have one of these installed: http://www.productsandservices.bt.com/consumerProducts/displayTopic.do?topicId=25075