From what I'm aware, these games are all just straight ports of the originals. Epinions doesn't actually have a place set aside for analyzing downloadable content off of specific platforms. They do, however, have a classic console game section where you can review those same games (where available) right here:

http://www.epinions.com/Classic_Console_Games

I was actually thinking about this myself. I would think just adding it as an Xbox 360 game an in the title specifying whether it's an disc for the console or whether it's downloaded from Live Arcade for instance:

title 1: Gears of War for Xbox 360
title 2: Geometry Wars for Xbox Live Arcade

Both titles are within the Xbox 360 category. The same would go for the Wii's virtual console as well. I'm just going to check with Garrett to make sure that this is kosher, but I assume something should be done about it since these are becoming more and more popular and it is something you purchase to play on the console.

So just email me (kjell1979@gmail.com) any Xbox Live Arcade games you want added and once I get the green light, I'll throw them up.