+1 for talking with your Dell rep. You can easily save at least 10% off retail, which will probably help quite a bit. They'll also usually just throw in things like iDRAC enterprise.
If you're needing to actually use 128 gig of RAM in that R710, then the essentials licenses just won't cut it. They're max 32GB per socket, so you would only be able to use 64.
VMware faced a lot of criticism (and rightly so!) with their new licensing, particular for small shops wanting to get started. In that light, another option entirely is to start out with 4.1 instead of 5 (no RAM limit in 4.1). For a single server, there's no real big difference, and upgrading to 5 once you're ready (and the budget is there) would be very simple and straight forward (providing you have a good backup in place to save your ass, the upgrade itself is about a 10 minute procedure).
You might as well order the server with more NICs as well (6 is usually the minimum with iSCSI). It won't add virtually anything to the cost, so you might as well just do it right away.
And props for EqualLogic's when you're ready for one. They're wicked little SANs, particularly in smaller deployments. You probably won't need/want two right off the bat, though. I recently deployed 3 R710's to a PS4000.