My parents recently changed ISP's and were sent a new ISP branded router - I set it up with that initially, then transferred the settings to their 'old' wireless router.
The old router was almost 1mbps faster than the 'new' branded router, and the ping was faster. So while I accept that a 54mbps router should be the same as any other - in practice I don't think that's the case. I believe the quality of the router can have an impact on the overall quality of your connection.
PCUK - what wifi router are you currently using?