Essentially, everything Bitt says is correct. He did leave out one detail -- fixed speed hubs only talk at one speed. If you've got a mixture of devices at different speeds, they'll either not work, or go at the slowest speed.
What you might consider is a dual-speed hub, which will allow you to have a mixture of 10Mbps (the empeg) and 100Mbps (your PC) stuff, without everything slowing down to 10Mbps. To oversimplify, a dual-speed hub contains a hub for each speed, with a single 10/100 switched crossover between them.
If one had only one PC and your empeg, then one would use a 10Mbps hub, because they'll be talking at 10Mbps anyway. If one had two PCs and an empeg, then one would use a dual-speed hub, so that the PCs can talk at 100Mbps, but they can talk to the empeg at 10Mbps. The Netgear DS104 and DS108 (depending on how many ports one wants) are ideal for this. You've already got enough gear to overflow one hub, so this doesn't apply to you.
However, as Bitt also says, 10/100 switches aren't much more expensive than 10/100 hubs these days. If you want one of these, I'd recommend a Netgear FS108.
To put things in perspective -- as I mentioned on another thread -- empeg Towers has a mix of DS108 and FS108 stuff. At home I have a pair of FS108 switches.
Mmmm. Pretty blue colour. Flashing lights.
edit: "oversimplify slightly" better get rid of that before Bitt notices