What switch do you recommend

Check the Equallogic support matrix for an idea for what switches are validated/supported/recommended. It is not limited to just Dell switches (there are some Cisco, Juniper, and Brocade options listed).

First you'll want to upgrade to dual switches on each floor and LACP them together. You could stack them, but this has the major downside that if you ever want/need to upgrade the switch firmware in one or both of the rooms, that you'll need 100% downtime in that room.

In my next part I'll stick to Dell switches as this is a Dell message board.

I'd skip the PC6200-series unless your budget cannot fit a better switch. The 6200 is a decent switch, but it's on its way out (can see this by the fact that Dell hasn't upgraded the firmware on this switch since the 3.3 series (all the 7k and higher switches are now on a 5.x firmware). The Force10 S25 series is a better switch than that PC7024, but if you are considering upgrading to 10Gbit at some point, maybe you can consider a pair of PowerConnect 8132s in each room. The non-F version uses RJ45 ports that can do 1Gbit and 10Gbit, so you can initially just use the current EQL units, but newer units could be 10Gbit units. You'd want to get the optional QSFP+ modules for each switch and 2 cables for each pair so you can use these 2 40Gbit ports to LACP the switches together in each room.

If you want to use an LACP between the 2 rooms made up from both switches, you have a harder choice to make; stack the switches (with the downside I mentioned above), or upgrade to Force10 S4820s as these offer the ability to make a port-channel across 2 non-stacked switches (the PowerConnect firmware doesn't offer this).

Cisco and Brocade offer similar features (to run an LACP across 2 non-stacked switches), but I don't know what exact firmware and/or switches would offer this.