Phone to run Bet2go, Betfair and internet simultaneously

Any advice much be much appreciated:

Contracts up 2moro with my Sony Ericsson K660i which has been a superb little phone (although a little dated) enabling me to flick between the above 3 platforms with ease (each continuing to run alongside each other in the background). But it is time to move forward.

Im sure theres plenty like me who rely on the 'aboves' when away from the laptop. Can anyone confirm whether a Blackberry or a Nokia E71 would allow the same performance. Or any suggestings other phones would be most welcome. Really trying to avoid making a purchase now and having to *****about round the shops at xmas with returns n all....

Many thanks