Loads of people will argue with me here but yes. Valve actually recommend those
settings for internet play and although higher settings benefit CS 1.6 it seems
valve are right and those default settings give very good results on a wide
range of servers for CS:S.

Many people and server admins insist that higher rates are better but I trust
valve as they wrote the game and the defaults work well for my 2Mbit ADSL
connection.

See here for what valve say http://tinyurl.com/b9dbx 

Default for the win.

There is a faq about this somewhere on the steampowered web sites, but I
can't find it right now. But here is some good info from valve:
http://www.valve-erc.com/srcsdk/general/multiplayer_networking.html

Averyone has thier opinion too, here's my two pence worth.

The default tick rate for a CS:S server is 33, sometimes people change
it to 66, or even 100. But you can't display more updates than your
monitor's refresh rate, which is typically around 60. Also the server
won't send more updates than the tick rate.

I tend to use cl_updaterate 60
and cl_cmdrate 70
with a rate of 15000

if you look at net_graph 3 closely you will see that the bandwidth
rarely goes up to 10k/S ( busy servers 20 people+ when everyone is in
the same place ) so you can probably leave the rate alone at a default
of 9000

The updaterate of 60 will only help when the tickrate is higher than 33.
 So the default values are ok for ADSL but have been setup to allowe
modem use. So you could try something like this if you want to run on
standard servers, this probably won't cause any problems, but note that
setting your update rate very high can cause problems with choke if the
server has a rate limit or bandwidth problem:

cl_updaterate 35
cl_cmdrate 45

nothing wrong with them really, but the admins on my server will almost
certainly ask you to raise them (or do it for you) to at least 75.

I'd just leave them as they are.