Actually, the 2 Hours for movies only applies when everything is at max (minus the WiFi, of course). Max Brightness, Max Volume, etc. If you use it at average to low brightness, and with average volume, you can get away with 4-5 hours of video playback. Although, that may be shortened to 3-4 hours when playing a movie on UMD.

In my opinion, you should only buy the handheld in which you see suited towards your needs. If you prefer the more "new and innovative" style of games, then the DS is right for you. However, if those types of games don't appeal to you, and you want some more "home console experience", then the PSP should fit right within your gaming spectrum. Also figure in where you will play the handheld, what accessories are immediately mandatory (screen protectors, carrying cases, etc.), and what you want to do with the handheld.

You must factor in that if you are getting a PSP for media playback, that you must be prepared to shell out some money for some good storage. For music-only, the amount of storage shouldn't be too high. For movies or TV shows (etc.), then the amount of storage should be high. You may consider buying a Portable Media Player with a good-sized internal HD for a few hundred more.

The DS is all about the games, which saves you some money. Also factor in that some of the games will be lower priced than that of the PSP's games (except for the $39.99 priced games, which appear for both handhelds).

What it really comes down to is this: how much are you willing to spend, and how long you want to play the games. Or, if you have the money (which isn't the case with most people), get both. In my opinion, wait and see.