How many clients can connect wirelessly?

[#1]

Apologies if this topic has been mentioned before. Is there a practical limit to the number of wireless clients a router will support?
Currently, my router (Thomson Speedtouch) has up to 4 laptops, a Wii console and a desktop PC connected wirelessly and a NAS drive and VoIP phone connected via wire. Without giving too much of a clue what somebody in the house is receiving for Christmas, an Xbox 360 will join the network (wirelessly) on, or after the 25th of this month. My daughter's boyfriend is becoming a virtual lodger and his laptop also occasionally connects to the network.
We don't use the broadband connection heavily, but the PC systems have an automatic backups (running constantly, in the background) to the NAS drive, that also doubles as as a printer server. Am I becoming over-ambitious?

[#2]

Around 250, usually limited by IP address range.
Bandwidth of course becomes an issue with lots of clients.

[#3]

@HPSauce
Thanks; I'd worked out there were 255 (+1 ?) IP addresses available. I was certain that bandwidth would become an issue before that, but I had wondered if at, say 7, or 8, the system wouldn't cope.

[#4]

The physical limit will be 253 addresses (255 - 1 x network address, - 1 x router)
Contention wise, it depends on your connection speed and the types of activity that you will be doing.
At a previous place of employment, we happily serviced 20-odd users on a paltry 2Mbit connection.  With simultaneous streaming and gaming would suspect that 2Mbit would  only service a couple of users.
However, it's unlikely that everyone will be using every device simultaneously.  In my household we have plenty of devices that connect via the broadband (3 laptops, 4 PCs,  3 phones, an XBox, a Media Centre PC and probably various other bits and bobs) and general usage is fine
Cheers
B.