Can understand the "not wanting to be odd one out"...
Does the Streak not have option of headset so you would not need to hold it to your face?
I clicked the link in your post again, went off and got into an argument about porn with someone, and have come back and there's still nothing but a nice blue background on the O2 site. However, a search with Yahoo! came up with some firm giving a Bluetooth headset for use with the Streak (OK, not great if you have earrings, perhaps but no need to hold a slab to your head (whether it be the Dell or an iPhone slab!)
Had not been aware of the differences in applications, to be frank, but that's because I've not "gone with the flow" (strapped for cash!) so no iPod or iPhone let alone an iPad for me... though did see some Android based tablets at US$150 on Ebay recently, and might be tempted if only my home broadband was more reliable (using a Three mobile USB modem more than landline as it dies for up to a week when there has been rain).
I was just looking on the e2save.com site (owned by Carphone Warehouse) and see they have the Dell on a 35 quid/month contract (yuk!) but then got me wondering when I saw some of their other deals, on HTC.
Do you already have a laptop ? It is just that from personal experience I've yet to be really impressed by some small screen device. May be fine for composing a quick text message, but always seem too much hassle for proper websites, especially as some sites don't seem to make allowances for narrower viewing devices.
Rather than jump at some Android device before v2.2 is out, it may be worth waiting a bit, and seeing what options the networks offer for 'tethering' (where you could use the mobile phone for internet access when your laptop was unable to get a wi-fi signal).
It's meant to be simple with v2.2 (from the Google presentation in April/May on YouTube) to use the wi-fi in the phone to allow access (I think they had an iPad getting net access via the Android handset's mobile network, with the Android unit acting like a radio relay). With the HTC Wildfire on Three, for example, you get 'unlimited' data (would need to check actual limits) for about 20 quid a month. Fine as a phone, but if it had v2.2 (currently v2.1) and you were allowed to use laptop with it, would offer better value.
Or is it the 5" screen and apps which will "win you over" to wanting a flashier newer phone and not touch your laptop?