:facepalms: DUH!! I should have thought about these in the beginning:
1) Transferring files between computers using a wireless connection is going to be slow no matter what.
Granted Wireless-G can go up to 54 Mbps, that Megabits per second, not Megabytes per second.
So divide 54 by 8 and you get roughly 6.75 MBps (bytes is represented by a capital B, bits is a lowercase b).
However, that 6.75 MBps is under ideal conditions. Latency, distance between the laptop and wireless router, obstacles, and all that play a major role in speed. You'd be lucky to get more than 3 MBps in most cases...
2) Copying multiple files simultaneously will also be a factor--the laptop's hard drive has to do more searching to copy multiple files from multiple locations on the disk platters. Your Netgear NAS won't suffer from this as much, as it most likely has a RAID array, which is striping the data across multiple drives.
3) Belkin products are notoriously crappy. You get what you pay for with these. If they performed as well as better consumer-grade routers, then they wouldn't be as cheap.
If you want faster file copies, use CAT5 between your laptops/NAS/router.
4) The reason you seem to be doing okay on the Internet is because your connection is only 1.5 Mbps. Again, divide by 8 = 0.1875 MBps. Since you're used to that speed on the Internet, of course you're going to say it's fine! However, copying gigs and gigs of files from PC to PC or PC to NAS over a wireless connection, and it doesn't seem as fast anymore.
Try the reverse: copy your gigs and gigs of stuff over the Internet and copy a few text files from one computer to another over your wireless. I guarantee you that your Internet's not going to seem so fast nor is your wireless LAN going to seem so slow...
