Most of the computers are new and have 1000Mbps nics.

Since we will upgrade the switches to faster ones would buying ones with more features such as cascade cable enabled switches and ones from Cisco work better than the run of the mill low end ones we currently use from a wide array of manufacturers?

I assume connecting computers and the console they use the most on the same switch would work better than putting all computers on one switch and all consoles on the other...unless of course they had cascade cables between them.