To expand further on my previous comment:

... "Despite the large display on the Streak, we were disappointed by its on-screen keyboard, which caused us much frustration with mistyped words during our tests. Dell has used the extra screen space to graft on a numeric keypad rather than make the keys larger, which is a missed opportunity in our opinion" ...

O2 have removed the numeric keypad on Android 2.1, although I still find it a bit fiddly. I've see an alternative keyboard called Swype, which looks amazing, but I haven't been able to download it since it is on a closed beta.

..."Also like other Android devices, the Streak supports multiple screens that can be accessed by a sideways swipe gesture. On the Streak, there is just one additional screen either side of the home screen."...

While there are only 3 screens initially, you can add additional home screens in Android 1.6, up to a maximum of 5, by pressing the '+' on the screen selector page.
In O2's Android 2.1, you always have 6 home screens. This is actually a (minor)problem since you cannot get rid of unused home screens.

... "Anyone considering the Streak to access web-based applications would also be well advised to test it out first, ... "

People should also think carefully about their bandwidth requirements before using the built-in browser. I installed Opera Mini, since it compresses the datastream by 90% or thereabouts. The Streak is a media-heavy device, and you'll get through a lot more data than you expect. The O2 dataplan is miserly, and a better alternative would be either an unlocked device direct from Dell UK (beware that O2 lock their phones for a full year, and the Dell USA phones are locked to AT&T), or alternatively you can still use the O2 locked phone on GiffGaff which provides far more generous data allowances. Don't make the mistake of starting a long contract with a low data allowance.

The 2.1 I am using is an o2 beta build - the final version may differ, and Dell's version may also differ. However, it really is a vast improvement over the original 1.6.

I have the Streak, and I really like it despite some glitches.

Mine has the 2.1 update, which is a big improvement over the 1.6 in terms of usability and responsiveness, although I'm still waiting for the 2.2 in order to get flash, JIT, and so forth.

The Dell accessories are astonishingly expensive. The 30-pin connector is PDMI, supposedly a standard for media devices, although at the moment only the Streak seems to use it. If it becomes more popular that would be good, since we'd be able to buy a third-party alternative.

The size is perfect for me - just small enough to fit into my pocket, and big enough for my iffy eyesight to see a webpage on the screen easily (landscape orientation). After all, what's the point of having pixels you can't see? :-)

If you intend to use it *primarily* as a phone, then I wouldn't recommend the Streak unless you also get a bluetooth headset. If you're looking for a general-purpose device that can also do the occasional phone call, then it's perfect.

If the Streak came to Verizon, and improved the keyboard to get rid of the num pad (or atleast let you switch it on/off) I'd be an instant customer. I find smartphones with smaller screens have an inferior internet experience, and texting on them sucks. Smartphones with sliders usually have smaller screens, the notable exception in the US is the Galaxy S pro with a 4" screen and slider but it's not on Verizon. So I guess I'll wait for the rumored 4" slider Droid Pro, if those are really the specs, or for Dell to diversify carriers.