The question should be, what are your needs.
On a switch, you should ask yourself how many connections are you planning to have (port density) and if VoIP will be implemented (think about Power over Ethernet -PoE-) as well as 10/100Mbps ports or 1000Mbps ports.
Switches can also provide full routing features if you are planning to have multiple VLANs or just connect to a metro-ethernet connection out to the internet/intranet.
The most populars are the 3560s and 3750s.
As for a router, you need to ask yourself the same questions ... most models are modular but you need to think about how many WAN slots or LAN interfaces you would need. The most populars are the 2800 and 3800 series.
You can't go wrong with either one.
