Many old/unused routers can be re-purposed as simple wifi extenders to bring along a wireless signal a few feet so you can continue to use an ethernet cable. That's what I recommend you do instead of dealing with finding the rogue dongle that happens to be compatible. Grab an 'N' spec Linksys router (w/ 1+ ethernet ports) for $5-10 and give it a go.
FWIW, there are plenty of friendly experts here in the PC related hardware forums who can show you how to rig up this system.
I have a 58" Panasonic Viera VT25 TV, that I used to have hardwired to my modem for use of the Smart TV functions, but now my fiancee and I have moved in together and given the way the room is arranged, hard-wiring the ethernet cable isn't really a possibility, so I'm starting to look at what my best options are for a wireless dongle to take its place.
Having done some research, there is a Panasonic branded one, but it looks like it has gone out of production along with Panasonic's TVs, so what would you recommend as the best dongle for me that will work with my VT25?
Not looking to spend a fortune, but I want something that will work, and won't crap out on me after 6 months, which a few other dongles have.