All depends what you want. One is a portable media player, one is an internet tablet, and one is a phone. The NIT has some overlap with the other two categories, might be comparable or better than the Archos for some media playback and surfing. Then again, if the video out is important for you to play movies on any TV, then the Archos is probably a better solution. The HTC is a phone... the other two are not.

As for browsing, I would think to go for the device with the biggest resolution and biggest screen size. I like the 640x480 on the NIT. Don't think I could live with anything smaller.