It may not be just Best Buy. It's just that Best Buy seems to put their stock on the retail floor. 

I'll go to the mall today, so I'm gonna pick up some anecdotal evidence and report it here :P

Same here in Toronto, Canada. Best Buy's and Futureshops with huge piles of PS3 (my son works in one and the PS3's just aren't moving), smaller piles of 360s (those are moving nicely) and no Wiis. DS's are started to become supplied constrained here too.

I report for the south of holland.
I went to one of the biggest city in my region today and checked how the stocks where here are my findings:
Media Markt:
hardware: no wii's / around 70 - 40 gig ps3's / around 100 pieces of xbox360 mostly the arcades
software:
3 rows of wii software and in front of that piles of more then 50 games ( around 5 or 6 piles ) and they where just restocking no super mario galaxy though or any of the bigger games.
2 rows of ps3 software not as much games as the wii.
xbox360 around 5 rows of games a lot still left though.

Van Leest:
hardware: no wii's / I saw 5 xbox360 and 1 ps3 in the showroom with a sign that they where plenty available for both.
software: a lot off all just no super mario galaxy ( allthough they got a new shipment which was not priced seeing as one of the clercks showed the game to a friend)

Freerecordshop : same thing as with Van Leest

Bart smit ( TRU a like but a lot smaller) : no wii/3 ps3s / 7 xbox360 software everything except. Yes super mario galaxy

Intertoys( TRU a like but a lot smaller) : no wii's / 2 ps3's / no xbox360 ( atleast not visable) software a lot no super mario galaxy.

edit: forgot to mention I did not see re:uc / wii zapper or anything available even the charge stations where sold out.

I seen a few copies of rachet and clank and Uncharted , Halo 3 and Assassins creed though

A female asked at Van Leest if they had the pc version of Assassins creed the clerck had to look so I told her it would come out in january then the clerck was like oh yeah...

It's always funny when you know more then them :P 

Brick & Atlantic City Best Buy & Circuit City, Toms River Target and Walmart and Toy R us.
Keep in mind where supply was "large" I only averaged I was Christmas shopping and thus in a bit of a rush to be counting each additional console except where visible stock was low

Bestbuy = Pleanty of PS3's about 60 mostly 40GB models but several 80GB as well at each bestbuy(they're 40 miles apart) 0 Wiis 0 DS's at best buy 15 PSP's(mostly the old "core" unit but 1 was the special star wars one) 360 = 0 core 6 elite 15 "Arcade" around 40 Premium around 80 and countless Halo eddition(I mean lot's... they had them back on the shelf with games, on display with the others 360's and a bunch up front near register.)

Target = About 8PS3's(it's all the room in the case the guy told me they had "enough" and laughed when I asked about stock 7 40GB's and 1 80 on display. 0 Wiis 1 Pink DS 2 PSP's 8 360's on Display(same case as PS3 but other side) 1 Elite 5 Premium 1 Arcade 1 Halo edition on display.

Walmart = 5 PS3's all 80 except 1 thats about the limit of their space. 0 Wii 5 DS - 2 Pink 0 White 1Red/black 2 Black 10 360's on display they had the arcade editions sitting under the 360 game rack not cased up for some reason(very un-walmart like)8 total with 1 of them being an original Core(why would they even try?) 2 Elite 5 Premium 0 Halo edition on display.

Toys R us = 7 PS3's 5 80 2 40 0 Wii 5 Ds(all pink is pink not popular?) 0 PSP on display but they had them behind the counter 5 360 All Halo edition I guess they're pushing them but I did see an elite and premium in the storage. Granted this isn't every store that sells them in my area but it's the ones I was in to grab gifts and Walmart I ended up in just because(I can't even remember why >.>) but it's a cursory glance of my area.

Oh yea for fotgot to mention... None of the stores had any Zappers except the Walmart that had Pink DSes. They must have gotten shipment because they had about 15. I was tempted to buy a couple for resale but I could not remember that they were going for on Ebay, so I did not risk it.

I work at Gamestop/EB and I keep an eye out for game systems and other such things when I'm out.

As far as at work, The Wii, 360 Premium, and DS pink and Red and Black. Guitar Hero 360, & Wii. Have all been sold out for signifigant periods of time. With the exception of the 360 premimum which we sell out of and the next day get a shipment.

Yesterday Toys R Us was sold out of all the items mentioned above, as was Circuit City two Kmarts and a Walmart in my area. (I was helping a friend find a 360 premimum finally got the last one at the other walmart in town.)

Strangely I went back to Walmart Toys R Us, and of course Gamestop/EB today and we had everything back in stock, (We recieved 15 boxes of stuff)

What I find even more promising however, is that for the last week our Wii game stock has dwindled signifigantly. We started out with maybe 75% of the games that the 360 had and were down to roughly 10-15% of what was left in stock as compared to 360.

Wii software has just been doing gangbusters this holiday season.  I can't help but wonder if the software performnace will be significantly up next year -- a lot of unexpected third party titles have been very successful.

The Wii software section in each store did look a lot lighter. The PS3 section at WalMart was absolutely crammed with PS3 games with each row being stacked nearly full from front to back.

Seriously, and to think that Gamestop was tearing up in Wii Software, I would think that Gamespot would be a weaker store for the Wii. To me that is more of a "gamers" store. Casuals like Target, TRU, and Walmart.... sales must be devastating at those places.

btw- I think BB and CC are in between stores, both Casuals and Core gamers shop there... that I why I like BB reports the most : ).