My HTC HD2 (current phone) is easily the best phone I've owned yet. The versatility of a phone that was released in 2009 and can still compete with most phones out on the market today doesn't cease to amaze me. Not to mention the fact that it can run pretty much every major mobile OS (save for IOS) gave me a chance to change up my phone at a whim. Although I will be upgrading to an iPhone 5 upon release, I will still be keeping this old phone around to continue tinkering around with until support for it stops.
I hear the HD2 is a great phone. Most versatile phone ever.
If I wanted to collect phones, it would start only with smartphones and the Wi-Fi browsing is fast enough where it doesn't bother me too much. I can live with 600Mhz processors if the browsing is good enough and it has enough RAM where it doesn't crash so often. Many apps are just website launchers, so I can always look up the info off the net.
I like to buy second hand phones off Craigslist. If the smartphone is at $60-$80 and in fairly good condition, I would buy it ASAP. My Bold bought for $80 used has a few nicks around the bezel, but I can always replace it.
My iPhone 4 only gets charged twice per week at most now ever since I got the Pixi (the girly phone) and the Bold (aka "THE BRUTE")
These smartphones are basically a portable PC in our pockets, so $60-$80 is a bargain sometimes for some of them. Cheaper than some mp3 players if bought used and far more useful. Harder to go back to dumb phones since it lacks Wi-Fi and such. I'd rather collect smartphones from about 2008 and AFTER. I can tolerate its speed. I would still be using the original iPhone and could tolerate the browser speed if I never sold it and it didn't keep randomly rebooting on me at least twice per week.
For older phones, I like...
Nexus One (seen one used for $100 at CL just last week!)
Xperia X1 (even though it is slow as hell, I love the design)
HTC HD2 (dual boot WP7 and Android. Nuff said.)
Samsung Focus (less than a year old, but this one can be bought used at $150 sometimes since WP7 is unpopular like webOS)
The newer ones from this year, I like...
Xperia Play (first PlayStation phone although my PSP already has emus)
Samsung GSII (for pure web browsing speed, Android is the way to go)
BlackBerry 9900 (the 9000 classic design returns)
Nokia N9 (I miss owning a decent Nokia phone)
Some great phones have been mentioned here. SE K900i was definitely a classic. Never had one, but Xenon flash inspired Nokia to add it on their N82.
And I am beginning to understand the appeal for BlackBerry. Their premium brand for business users and young professionals just doesn't disappear after a decade. I can't help staring and using my Bold right now. RIM will always have their niche.
What made me start this thread was because I was viewing phone collection videos on YouTube last night. And when I collect, I prefer a quality collection over quantity and most I've seen were cheap prepaid flip phones. I am very picky on phones I want to buy next and it gets planned months ahead. I might just get 3-4 smartphones. One for WP7, Android, QNX, and Meego (N9). From there, I can end it. Although HTC HD2 can eliminate a couple of them.
I like how this guy has the Xperia X1 (2008) and Nexus One (2010) in the same video. Very rare to compare the X1 vs the N1.
iPhone 4 vs Nexus One vs XPERIA X1 vs K510i Boot Test
http://www.youtube.com/watch?v=n-iALrzDgTQ
^^ Two older phones I want to add to my collection. Xperia X1 is slow though compared to even the Bold.
X1 vs G1 vs Bold (the girl is cute)
http://www.youtube.com/watch?v=VCr_nldJRKo
Noah Kravitz's All-Time Top 5 phones
http://www.youtube.com/watch?v=924qeeFHjTw