Others have said much of what I want to say, but I'll go into a bit more detail.
The good part is that price is no longer an issue.
Since you're obviously very interested in the experience that the PS3 offers, the 360 seems to be your best bet, as it offers a very similar experience. The drawback is that the two might be too similar: nearly every third-party game is shared between the two systems. So take a serious look at the 360's first-party offerings, and ask yourself it they entice you enough to make you want to purchase the system. Remember that many of those titles can be gotten for very cheap by now, which is an added bonus. Also, make sure to look at XBLA, as it has some excellent exclusive games as well.
The Wii is both easier and harder to recommend. It is markedly and deliberately different in what it has to offer compared to the HD systems. The upshot is that nearly every good game on the system, released and upcoming, is an exclusive. The downside is that many of the best titles (i.e. Nintendo's own) are still at full-price, and aren't going to drop anytime soon. Also, make sure you think long and hard about whether you'll appreciate the values behind the Wii, as they're very, very different than those on the HD systems: online and good graphics are there, but in smaller quantities and with much less emphasis.
If online gaming and HD graphics are your thing, the Wii is a waste of your money. Also be warned that the Wii is deficient in certain genres, most notably FPS, fighters, and racing (although that seems to be slowly changing), and what it DOES offer in those areas are still different than those you'd get on the HD systems. Finally, and most importantly, realize that the motion controls are not 1:1, and never will be. That said, your concern about Sony's Wand is nearly irrelevant: the software is almost certainly going to be radically different, and it's unlikely that the Wand will ever be the centerpeice of the PS3 (in contrast to the Wiimote). Put that out of your mind when calculating your next purchase.
Also, don't overlook WiiWare, the Virtual Channel, or the complete backwards compatibility: the latter is especially important if you never owned or extensively played a Gamecube, as that system has several fantastic games available for low prices. And it's not like the graphics are that much worse. 
The DS is very easy to recommend, but it really doesn't seem like you're that interested in it. Again, know that it's a completely different experience from the PSP, and that the two offer very different software. If you like what you see, go for it (the fact that you can get it, and its games, relatively cheaply makes the DS less of a risk).
I can't tell you more without you telling me what you like in your games.
| sc94597 said: I don't want to bash other peoples recommendations, but I would like to say that the Wii is a bad choice when in comparison to the DS. The Wii still needs to build up it's library for one thing. The DS crushes it in that area. |
I strongly disagree. I would go so far as to say that the two systems offer dramatically different experiences, making direct comparisons moot.
