Generally, it's more than adequate. My home network:

1 Apple Airport base station (for client 802.11b access, 128-bit WEP -- I replaced the WaveLAN siver with a gold card)

2 LinkSys WAP11 base stations bridging my home office and my living room LANs

at least 2 notebooks simultaneously web browsing, listening to streaming media, logging into/transferring files to/from machine on my home office LAN or systems in colocation facilities via 802.11b PCMCIA cards

at least two handhelds doing similar things, plus running either VNC or Microsoft's remote access client (basically the same as VNC, but for Windows) via 802.11b cards

Occasionally one of my Tivos also pulls its updates via a Toshiba Libretto running OpenBSD and networked via an 802.11b connection.

1 SliMP3 on the living room LAN streaming MP3s from Live365 via the 802.11b bridge, or from my MP3 server on my home office LAN (also via the 802.11b bridge)

I've had the SliMP3, both notebooks, and Tivo all sucking data simultaneously, without placing any strain on that 11Mbps pipe.