CAT5 OR CAT6

If i want to hook up a Sony PS2 to my broadband box would
i use a Cat 5 or Cat6 wire?Thank You

Any good CAT 5, 5E or 6 should do okay. Needs to be
a 'straight-thru' or 'patch' for the PS2 to router. If
connecting directly to computer you'd use a 'crossover'
type cable instead.
Might be a good idea to be sure you get the cable with
gold connectors having more than just gold plating, esp.
if you plan to disconnect/reconnect it many times. Too
thin a gold-plating will wear off quickly.
CAT-5E and 6 are for very high data transmission rates,
and CAT-6 has an improved insulation between the wires
(less noise).
Don't quote me on this but I think the data rate of a PS2
isn't going to be high enough to matter.
Here's an example of a place with 50 micro-inch gold
connector patch (not crossover! ...remember) cables:
http://www.aedwis.com/cat5.html#patch

Guess I should have pointed out that although this is
still gold-plating it is thick enough to be okay. Others
are very, very thinly plated, which is why I was trying
to emphasize that for something you might be unplugging
and replugging a lot.