any bb speed will be fine.pings bottom out at a certain point and wont get any lower with faster speeds.i 1st started bb online gaming with a 512k line and am now on 'up to' 6 meg and have found no difference between the 2.
I play UT2004 online, sometimes on 32 player servers on, to start with a 512k connection, I am now on a 2Mb connection and there isn't much difference.