I'm using the USB SCV modem and it work. I feel that the ethernet one is unstable cos previously i'm using the ethernet one and it suck. i'm happy to use this USB version but the problem is the cable is too short.
i'm using an intel 82559 based NIC, 2nd hand, pulled out from some corporate computers - for only 25 bucks. in fact, now it's selling probably 10 bucks along 4th level of sim lim square. check out the 2nd hand stores for stocks.
this card supports all the bells and whistles for nics. up to 100MBit/s. PLUS network management if you're "siao" enough
The connection cable from the cable modem(SCV MaxOnline) uses CAT5 ethernet cable, while for some ADSL modems use usb cables.
In order to connect your computer to the cable modem, you can use an ethernet card, a broadband usb adapter (like Trevon_Tan mentioned) or PCMCIA card for laptops. As such, I think that it doesn't really matter which cable modem you use. You can try to request for a usb adapter instead of an ethernet card when you subscribe to SCV MaxOnline.
If the ethernet cable from the modem to the computer is too short, you can purchase a longer piece from shops at SLS.