Juniper makes carrier core routers, and through an acquisition they make a CMTS line card for a darn good cable head-end router, through their Unisphere acquisition they have a SMS box and a funky edge router (and some other products that I don't think matter), and they just bought Netscreen.
spidey07, Enterasys (formerly part of Cabletron), Nortel (who bought Bay, who bought SynOptics), and Avaya (formerly part of Lucent, who bought Cajun), and Force10 (start-up) are all enterprise switch vendors who you shouldn't actually buy from, but if you're just looking at the market, they're folks to look at.