I think that eBay is a pretty good gauge of what is popular, an arbitrage of the market of as high a caliber as one can access for free.
Recently I went searching for Angels memorabilia and decided to look at completed auctions and sorted the list to reveal the highest priced items first. Since Items that sold were indicated with their price in GREEN, it was easy to scan down and see what big ticket items were selling - therefore, what was most popular in terms of memorabilia and apparel connected with the (baseball) Angels (my search term of preference is in the title of this entry and searching in the offseason avoids the morass of tickets available on the site as well as provides a lot more bargains).
Since October 18, the only Angel to have personal memorabilia sold on eBay has been Jered Weaver.
All the Vlad jerseys are unsold. Everyone who wants one has one and does not want another. Howie Kendrick merchandise goes begging. The jury of the wallet is waiting on Brandon Wood. Any player else who contributed to the 89 victories in 2006 is orphaned at the checkout line. But Jered Weaver's signature and jersey garner the occasional high-end offseason sale.
I wonder if this means the mullet is making a comeback soon...