With a "managed" switch, you can also do other fun stuff like port, protocol, and subnet-based vlans (to limit broadcast traffic). You can also do trunking (or ether-channel, for you Cisco weenies) for redundancy and extra capacity. Some will even allow you to run basic Layer 3 code and do limited routing (static routes, RIP). You can also force port speed/duplex (helps with some recalcitrant Taiwanese NICs), and, of course, do the filter or SNMP thing. Don't forget SSH support. My advice, forget the web interface (useless) and learn the CLI.
Did I mention rate-limiting?
-j