I find with TF2 I need 50-60K minimum on a 24 slot server to maintain 0-5 choke with my client's cl_cmdrate and cl_updaterate set to 67 (and letting the server automatically set me to the sv_minrate value). My pubs used to be set for 100K/unlimited by NFO but I reduced them to 60K min/100K max with no issues.
My UGC highlander match server, however, is set to 20K/60K per their rules and at 20K there is about 50-60 choke and only about 33 ticks coming in. Theoretically, doubling that rate to 40K should get me about 66 ticks but I find 50K or 60K to be better for me choke-wise.
With net_graph 4 open, if there is a ton of choke and little to no loss, lots of empty spots in the graph and your "in" value on the far right is nowhere close to "66.7/s" then your rates are too low.
Example of crappy rate (the competitive mandated one (20K minimum) to make everything fair):
http://cloud.steampowered.com/ugc/52...6C12ACB4E395A/
Example of good rate (60K minimum on a 24 player pub):
http://cloud.steampowered.com/ugc/52...817D7D09EE41E/
My computer consists of an i7-2600K @ 4.5GHz and a Radeon HD 6970 with a 120Hz ASUS VG236HE LCD monitor, so my game can maintain ~120FPS with VSYNC enabled (I mention this because you would ideally need to maintain 67 or greater FPS on a 66 tick server with 66 tick client settings to have 66 tick both in and out constantly).