I've been using this device for about 10 weeks now. I see it as a portable computing device with voice and data, GSM and 3G and 3.5G connectivity, and therefore expect a whole lot of flexiblity when it comes to tweaking, tuning, but also well thought out and polished. A bit disappointed in some areas:
1. App manager isn't exactly the most ideal/suitable app management solution on a portable device. It takes too long to load up completely, requires a lot of power and cpu cycles. Sure, you can argue that one shouldn't install apps while on the go.
2. The e-mail app sucks. Sure, there are other apps to replace the e-mail app, but I have the expectation that Nokia shouldn't create a half-*** app and think the community will deal with it.
3. The web browser's "expand to full screen" and "escape fullscreen" icons just don't match the icons used in Maps (the direction of the arrows). It's just another example where the product is not well polished.
4. With soooo many different kinds of transitions being used on the N900 (some are even inappropriately used/picked), can't Nokia use one for entering and escaping fullscreen, rather than full screen flicker?
5. No multi-select in e-mail...what are you? Apple Mail on the iPhone? Even e-mail apps from 10 years ago has multi-select...bloody hell...and you (nokia) are trying to sell this platform as a powerful portable computing device? Get the software right, the user experience right, the user interface right...damn it.

While the hardware is definitely what I love, this product's truly limiting factor is that it is (feels like it, at the very least) a half-*** job, prototype, a product that they just push out the doors to get money from customers to fund other projects. Nokia isn't focused and committed to the N900 (nor did they for the N95 and N97....this been going on for a loooong time). For the past few years, Nokia has really been behind in getting things right. The lack of commitment to come up with a thoroughly thought out, well planned, well executed product (and platform) is really tiring from a customer's view point.

....alright, I'm done whining, ranting...and yes, I've probably wasted some of the readers' time here (no need to point this out as it will further waste your time).