I've been racking some new kit today. A couple of simple boxes for mail relays (and spam filters), and a backup server.
We've gone for the new Sun X2100 M2 for the mail systems. Something lightweight, but fast to handle the load. And very affordable at that.
We got an X2100 a while back, and it's been a huge success. We run our trouble ticket system on it, and it's not just faster - it's revolutionized the way we work. Before, doing anything with the trouble ticket system was so painful that it discouraged anyone from logging or handling tickets. Now, it just flies. We're hoping for the same from the mail system, which (and I guess everyone is getting the same experience) is getting swamped by the spam deluge.
The backup system is nothing special, I've put in a V240 with a C4 library. The only thing to say about this is that the C4 library is a deep beast - it barely fits into the Sun 900 rack and that's without being cabled up yet!
And I was just sitting down after that when a try-and-buy T2000 showed up. That's in the rack too, and it all looks very impressive.
We're interested to see how well the coolthreads system works. In general, I see increasing use of opteron systems, but we still have a number of sparc based applications that we're going to have to run. It stands a good chance - apache, tomcat, with a database or proprietary search engine at the back - so we're optimistic it'll be a success.