Bear in mind time of year, always best to buy big from Cisco in July as it's their end of year and can get you a further 6% off. You'll get sector discount (around 40-50% for public sector), then you can get 6% for end of year, then a further up to 6% for 'buy-back' of old kit (doesnt have to be the kit you are replacing, so make sure you keep hold of those old cisco switches!!).
Then you'll also have their 'special' offers, they are doing bundles on Nexus at the moment, Nexus 7010 bundles, 5548 bundles as they are trying to push these for datacentres rather than the Catalyst 6509E's. They've just released the Superviser 2T's today for purchase and delivery in July which make the 6509E's a very attractive proposition against the Nexus range.