Running Debian Linux on a recent model of web server--any problems?

We want to buy a server for our research project. We will run mostly web applications. We want to run Debian Linux. But the server manufacturer says, in its maintenance agreement, that they support only Redhat and Suse. The server models we are considering are recent.

Does anyone of any common or recurrent problems on server hardware when running Debian? I have heard of certain possibilities, for example, that network graphics cards won't work properly. But my gut tells me that Debian might run properly on any current server model.

Any ideas?