Into and Medusa, we used to have that problem with ds1, he never really played so ended up with piles of dvds and books rather than toys. Its only really the last 2/3 years or so that he's wanted more, mainly games for his ds and computer, lego and collectible things though, rather than things to actually play with.
The Lego Ninjago etc, is stuff he wants to collect, but doesn't really play with - although he will occasionally play with his brother, but only the rule-led battle spinning for points thing rather than an actual game. iyswim. The lego sets are to build and display, never to be touched again and are collectible as well. About the only thing he will play with are his Beyblades, he got into them because they're collectible, but then discovered he likes watching them spin (they're battling spinning top things).
He will play the trading card/top trumps type things with his brother (more rules, facts and numbers) and more recently has been interested in driving the remote control Zibit robots around.
Over the years he has asked for stuff he's seen advertised on the tv and then not even played with it once, so we have to be very selective or its all a complete waste of money. These days he tends to ask for things he can obsess over collect and things that his peers are getting so that he has something to talk to them about at school.
Drives me potty. Every year I spend hours searching the net for obscure collectibles that are impossible to find or ridiculous prices. Half the stuff the manufacturers just change one tiny thing on and then pronounce it a 'special edition' or 'rare' and your collection isn't complete without it. 
That said, recently he has become quite interested in certain board games. I think its come out of the 'teamwork' SEAL group they're doing at school. He's actually asked for a board games compendium (which I forgot to put on my list) and another game called Forbidden Island which you can only complete if you work as a team - now that's going to be interesting! 