Hi,
let me advocate zeronconf vs. static IP a little more.
Charles Goyard wrote:
Keep dhcp on to satisfy the network topology, and try zeroconf.
Also, it can perfectly be that mdns is enabled by default on Raspian. You can check by issuing a "ping yourpihostname.local" from the raspi.
I find the static IP way a lot more time consuming and error prone. The IP you choose can be free at the moment you set it, but if a new computer pops up in the network, you can have a conflict. Example: on my network my printer has a reserved IP in the DHCP configuration. If you happen to pick this apparently available IP and I turn the printer on, that's a big mess, because you have not respected the network administrator's work :).
Zeroconf has been made for that: you know nothing about the network and still you're reachable by name. Easy, fast, default on Ubuntu and Apples.
Search "avahi" in this page: http://raspberrypi.stackexchange.com/questions/38/prepare-for-ssh-without-a-...
To have zeroconf installed in windows: http://support.apple.com/kb/DL999 (yes, it's supposed to be about printers but it works for the whole system)
Cheers,