We force updaterate and cmdrate to 66 so players can't set them to get an advantage.
Setting updaterate and cmdrate differently generally won't help you fix choke anyway (if your rate is set right).
Try changing your rate to something lower, like 25k or even 20k. We don't limit that as strictly.
Also, see
this thread.
And turn off anything else you have running -- even if you cap it. Your router (most likely) has to do NAT for all these packets and will definitely affect your gameplay.
Lastly, in your router, you might want to statically forward your client port (I think 27015) for both UDP and TCP to your computer. That way, when the router sees that port number, it doesn't have to do NAT (which modifies the packet and recomputes checksums) and can just forward the packet.
If you still have choke, make sure you don't have other computers using up your bandwidth -- sometimes I'll leave another computer on with a torrent program running and it significantly affects choke. If you can't control what other people do, consider a router that has QoS settings -- the WRT54G with the DD-WRT firmware is excellent in that respect IMHO.