(oh, I see you are with GitHub. Somehow I suspect you did not push for this downgrade.)
(followup to sounds: I'm not particularly pro cisco except that all-cisco lets you avoid interop problems. Since at least some of this is cisco, there's a good argument for all cisco.
I've actually used HP and Dell successfully for certain things, but only because I kept it as simple as possible.
In the past using other stuff was necessary at the high end, too, because cisco didn't provide 10GE very well, etc.
What I am against is cheaping out on your ~few aggregation switches, which I've seen other people do, when you're already spending good money on everything else. Maybe it's different once you get to Google or Facebook scale, but I've never been responsible for quite that many switches, and an extra $500-$1000 per 24 ports isn't going to kill you.
I actually prefer non-cisco substantially for routing and for security products.)