This is a getting to be a little infuriating. Why does everyone insist on going off-topic and not paying attention to my original question?
To
davevt31: A USB-based wireless NIC is required for those days I bring my work laptop home and desire to use it on my home network. That laptop's built-in G-adapter is of poor quality. So if you don't mind, I am not interested in hearing about PCI wireless NICs.
To
thecreator: Why go off-topic and talk about wired network connections? It's nobody's business really, but since you seem to care so much; I already have a computer sitting beside the DIR-655, connected via a CAT5 cable. Yes, I would probably use that machine for firmware upgrades.
With regards to your next point, my question re: Linksys was more along the lines of "what exactly is the impact to my (real-world sustained) speeds if I get a Linksys N-adapter rather than a DLink N-adapter".
And yes - clearly, it is my cash which would go towards the upgrades - why wouldn't it be?

Now, if there is anyone who wants to talk about
USB-based wireless Draft-N adapters, then please pipe up! I really don't want to hear from anyone else.
I did not open this thread to solicit general advice on my system configuration.