If it was me, I'd be going with the Nexus 3000s.
If you want single point of management, perhaps it might be worth looking at the Cisco 5548s or 56xx range of switches combined with a pair of 2248 FEXes. This would give you 10G and 100M/1G ports with a single management console, although the FEXes don't appear to have PoE so may not be suitable for end users needing VoIP phones for example.
If you can get refurbed Cisco gear, you can get some considerable savings even on relatively new Cisco kit (hence me mentioning the Nexus 5000s). I guess it depends if Smartnet is critical or whether you can use a third party support company.
AFAIK the Catalyst switches are still going, so a venerable 4900 or something 4500-ish would give you 10G ports (and VSS with 2 of them for hardware resiliency) Can't comment on costs though.
For vendors other than Cisco, I'd be giving whiteboxes running Cumulus a serious look. If you're familiar with Linux, then these might be a viable option, I'd have thought with a bit of puppet/chef/ansible that management overheads could be reduced. They also now have a VM for download so you can at least evaluate/test at a minimal cost.