My opinion on some of the points made here.

Battery:
Unless you have used the N900 extensively, complaining that they didn't use a better battery is silly.

Consider that by using the same battery as previous models it saves Nokia money not having to design and manufacture a new battery. Even better, once the battery dies it shouldn't be too hard finding an official replacement so no worries buying poor knock-offs or worse, not being able to find that specific model at all.

So its a win win situation, as long as the N900 has reasonable battery life (which by all reports, it does) then Nokia made a good choice. Stick to a tried and tested battery, avoid all the cost and risk of developing something new.

Keyboard:
It never fails to amaze me how people under value a good keyboard.

I would much rather have a thicker device with a keyboard with decent button travel than a thinner device where you get poor response. I had a lot of problems with my Xperia X1 keyboard because it didn't have enough travel on the buttons. The layout was excellent (although the size awkard due to the device being too narrow), like the Droid, but a good layout with poor response is useless. The Droid keyboard at least in the photos looks really cheap.

Speakers:
This one should be obvious, the bigger the device the better the sound quality can be. If you mount tiny speakers flush to the case you get tinny sound and minimal volume, but if you allow a little space you can drastically improve both loudness and bass response.

Again, the Xperia X1 was super quiet and tinny (I could never hear it ring in my pocket) because they favoured design over functionality. The slit for the audio was microscopic, if they had made it a little wider they could have had amazing sound. In fact everything about the X1 was style over functionality and the reason I sold it and switched to the N900 was because it seemed to fix these problems.

Thinner is better:
It really isn't. I do love my iPod Touch for being the ideal screen/device size vs pocket-ability but I find it far too thin to handle at times. Many times I have come close to dropping it because its so thin and light.

Multi-touch:
You ever tried doing multi-touch actions when you only have one hand free? Its a lot easier to do the clockwise/counter-clockwise motion the N900 uses than mutli-touch so once portrait mode works in the browser, it will kick the iPod/iPhones *** for one handed usage.

After using the iPod Touch extensively I find mostly I use it portrait. Wait, isn't that a negative for the N900? Perhaps for now, but I find also that I do not use multi-touch for the same reason so one of the biggest selling points of competing devices is null and void.

So overall, devices like the Droid do not seem so brilliant anymore, at least to me.