According to the site
ICv2, the top 5 Collectible Games for 2010 for the overall market were.
1 Magic: The Gathering
2 Yu-Gi-Oh!
3 Pokemon TCG
4 HeroClix
5 World of Warcraft
So it looks like MtG is holding on despite some cutbacks in tournament perks. No surprise about Yu-Gi-Oh, Pokemon or WoW - really expected them there. However, I'm surprised to see HeroClix on that list, since in my neck of the woods that game is long dead and rarely sold anywhere. They have another list at the above link that has the top 10 CG's for the 4th qtr 2010 specific to the Hobby sales channel/market. Rounding out the top 10 are D&D Minis, Legends of the 5 Rings, Naruto, Star Wars Minis and Axis & Allies. Again, I'm a bit surprised by the strength of D&DM's and SWM's as they were both discontinued earlier in the year.
Their list of top 5 P'n'P RPG's for the 4th Qtr 2010 for the overall market were:
1 Dungeons & Dragons
2 Pathfinder
3 Dark Heresy/Rogue Trader/Deathwatch
4 Dragon Age
5 Mutants and Masterminds
Great to see Dragon Age doing so well, since it's still just over 1 year old and great that a small publisher like Green Ronin can place 2 RPGs in the rankings. IMO the Pathfinder placing shows D&D 3.5/3.75 still has lots of legs. I fully expected WotC's D&D and Fantasy Flight Games DH/RT/DW to be on that list. I've heard nothing but great things about those FFG RPG's, but on a few sites I've read the occasional criticism that FFG's seems to have abandoned Warhammer Fantasy in favor of their other RPG's. I never played any of them, so I'm not really sure.
I don't know much about ICv2, but they appear to be a marketing company offering consulting services to the tabletop game industry. I'm also not sure why they don't have overall 2010 for the RPGs, but I'm guessing they just started reporting them.