175 is still ok, you really do not want to be in the 275-300+ range.
Some servers kick (in BF2) if you're over 150 for mroe than 3 tries, which I think is ******ed but whatever.
Wireless is terrible to play on unless you are right next to it, because the transfer rate and pings will fluctuates based on the environment around it. If you are connected straight to the modem or router your ping will drop since it's a straight connection.