cheap USB ethernet or a bit expensive PCI based?

an ISP at my hometown is offering approximately US$ 180 for a new cable instalation, the package includes one month subscription, a choice of Zyxel or Motorolla cable modem, registration, and a free instalation

my deepest concerns are the modems, does USB modems performs better or worse? because another ISP offering standard instalation with the usual RJ45 at approximately US$ 250 ... and I have very limited budget (going to buy that XMS mem modules)

thank you in advance

so it's recommended or not? I won't be playing multiplayer games anyway, just basic downloading, browsing, etc

how about bandwith? I need to download heavy files for my study (photography), high res images are a must, will the usb modems handles downloads the same as the "old" standards?

I'm too new on this stuff

usb is limited to 1.1 mbits. if your internet connection is capable of more than that, you still wont see higher than 1.1. also if down the road you want to add another computer to the same internet connection, you wont be able to use it with a router.

my computer is so fast, it completes an endless loop in less than 4 seconds!

It is better to use RJ45. A PCI NIC will offer better performance and RJ45 connection on the modem is more flexible. If you need to share the internet in the future you can just connect the modem to a hardware router. You can not do that with a USB modem.

PCI NIC is always better than USB NIC.