I actually bought about 11 DS games:
Castlevania DoS and PoR
Advance Wars DS
Pokemon Diamond
Super Mario 64 DS
Picross DS
StarFox Command
Animal Crossing WW
Metroid Prime Hunters
Mario Kart DS
Brain Age 2
But, after getting AC and before getting Picross/Brain Age 2, I got an R4. I bought Picross/Brain Age 2 saying I'd use the R4 to demo games I wanted to buy, and then buy them if they were good. After thinking about that for a while, I said fuck it. I sold all the games on eBay for a VERY good profit (I bought all of them except Brain Age, Picross and Animal Crossing used off of eBay). Now, I just pirate games on my DS and PSP. Fuck buying them.
But, one thing I hypothesize is that the reason the PSP has such a shitty library of now and upcoming games compared to the DS is because piracy is more prevalent on the PSP. People buying that thing are usually more tech savvy, and TBH, it's a plain flat out piece of shit with Sony's HORRIBLE official firmware. It surprises me how much better homebrew devs are than their corporate counterpart, it's just pitiful.
For example, using the homebrew app iRShell to replace your XMB, you can overclock your PSP (333mHz) and play mp3s while ingame or using the web browser. Using Sony's OFW or the XMB, you can't do that. Why? It's OBVIOUSLY not because the PSP isn't powerful enough, it's because Sony blows. Not to mention that loading pirated ISOs off of the Memory Stick loads faster than UMD, and takes less battery power and is more compact... If they would just make their PSP (Pretty Shitty Portable) better with their OFW, maybe people wouldn't pirate AS much. Because right now, pirating owns on the PSP.
Wow, that was a long post and tirade. Love my DS and PSP