Well, I gave in and registered, just to respond to this.
First off, yes, those are two ethernet controllers; presumably this is some sort of high-end hobbyist/workstation board. A 'PHY' refers to the 'PHYsical' transceiver, so seeing two specified means that each controller should, indeed, terminate in an ethernet jack you can use. (It's not entirely uncommon to see boards made ignoring/supplanting integrated features, like the NForce's MAC.)
Now, if you're using Windows, and have a working driver for your particular flavor (which *has* been a problem for many), the USB modem will work fine, though you won't have the flexibility to plug it into a cheap Linksys router. The problem is not so much that "USB sucks" or "USB DSL modems suck," but rather a general lack of understanding/support for the standards involved. If I can talk out my posterior for a bit (read: I don't know for sure, but I'll pretend I do; enlightened ones, please correct me):
-DSL itself runs over a link-layer protocol called ATM, 'asynchronous transfer mode.' You could conceivably do all sorts of wondrous info-superhighway things with ATM (traffic prioritizing for voice-over-DSL, digital TV, etc), but in practice, you don't, and it just encapsulates the PPP, IP, ethernet, or PPP-over-ethernet packets that make up your nice fast internet connection. Your provider likes ATM because they've been using it for their voice traffic for years, and it keeps things managable for them.
-When you have a "normal" DSL->Ethernet bridge ("DSL modem"), the box is "forced" to peel off the ATM layer, and do whatever may be necessary to spit ethernet out the other end. You might get left with a headache like PPP-over-Ethernet, but those are still plain ethernet frames, and just about every platform on the planet knows how to deal with them.
-When you have a USB modem, however, it's likely to be spitting out the ATM cells (packets, frames, whatever you call them) directly, since there's no reason for it to 'convert' to ethernet (and ATM does, theoretically, have features that ethernet doesn't). This would be cool, except now you're faced with a more 'arcane' technology that the fresh grads from Bob's House of Visual Basic just hired by DSLModemco might not fully grok... and which alternative OSes - even Linux (
http://linux-atm.sourceforge.net) - aren't likely to support off the bat. Add in some of the vagaries of USB itself- it's just becoming a mature technology- and you can see why people whine.
That situation was more dire around the launch of XP; nowadays, I think most companies' drivers have stabilized. I do believe there are a few USB modems out there that dump ethernet frames, rather than ATM, but it all depends on the technologies your provider is using, and even then, don't expect those to work easily under free *NIXes until/unless someone hacks the device codes into the appropriate places.
--
Basically, from my POV, whatever you have will be obsolete in 5 years. I'm guessing it'll be about 3-5 for the USB/ATM standards mess to truly stabilize to whatever PnP nirvana it's supposed to be, across the board... though as I've said, it's probably almost there on Windows, barring new version jumps.
--
That out of the way, you have two ethernet ports (and with a USB modem, you'd only need one, anyway), so you *could* get by with a hub and Internet Connection Sharing, rather than a dedicated router. Whether you'd want to put yourself through the hell of securing/relying on Windows is another matter, but 2k is stable enough for the task, barring worm attacks, ActiveX-induced trojans, mail virii, security-patch-induced-holes and so forth.
You probably *would* be happier with the ethernet modem and the Linksys, if for no other reason than everyone else on earth having that configuration. I just wanted to explain *why* the USB situation sucks; it's basically a bad interaction of good technologies, and now you can explain that fact to others.
