Funnily enough, my only remaining ThinkPad is actually a vintage one (clearly), a 365XD.
Unfortunately, I don't use it for anything serious, it's a collection thing. I decided to get one when Lenovo decided to try ruining the ThinkPad (between the TrackPoint buttons on the ??40 series machines, and the keyboard changes on the
X1 Carbon), as an example of what ThinkPads used to be. While I do still want a first-gen high-end ThinkPad (the 700/720), I figured a second-gen high-end (or derived) ThinkPad (750/755/360/355/370/365) would be rather more useful while also still demonstrating some of the earliest ThinkPad design (it's worth noting that the 750 launched only 11 months after the 700, and 4 months after the 720). And, the 365XD was the fastest of them, and was also better equipped to be a DOS gaming box (being Mwave-free, unlike things like the 755CX), so I got one.
Mine's a 2625-DEF with a 120 MHz Pentium, 40 MiB RAM (soon to be 72), 6.4 GB HDD, and a 10.4" TFT, with an Orinoco Gold for networking. (Funny thing, I've seen
modern entry-level business laptops with worse viewing angles. And this was a premium screen option, yes, but still, literally 20 years ago.) I'm triple-booting Windows 98SE, OS/2 Warp 4.52, and OPENSTEP 4.2 on it. 98SE is the main OS, OS/2 is because it just seems right to run it on an IBM machine, and OPENSTEP... well, it may not be "black hardware" in NeXT parlance, but it is black, it is hardware, and it's one of the few laptops that OPENSTEP had thorough support for (because Steve Jobs personally used ThinkPads with similar hardware).
I've been playing with it in 98SE lately, and 98SE can still run PuTTY, it can run older versions of Opera, and Opera 10.10 with JavaScript disabled is actually fairly responsive on most sites (and I'm writing this post on it). Toss MagnaRAM on there, and even swapping doesn't happen all that often (and when it does happen, it's compressed, which helps a
lot with performance on the PIO-only disk system in the 365XD and other laptops of this vintage). And then, the keyboard is quite nice to type on (it's not as nice as a good mechanical, but nicer than a lot of laptops out there), and it has real TrackPoint buttons. MP3 playback is rather taxing on it, but it can be done.
Now, would I use this as my main machine? Noooooooooope. Too slow for a lot of the things I do, and there's not a single OS with acceptable security for main machine duties. (At least it's not XP, though. Windows 98 is actually a far smaller target than XP, both because it doesn't have anything remotely exploitable, and because modern malware makes assumptions that only work on NT-based OSes.) But, it is nice for DOS gaming, and it also acts as a good go-between to other retrocomputers - it can access network resources, it has a 16550-backed serial port, it has PCMCIA for exchanging files with, say, a 200LX, and it has a "real" floppy drive.
What I actually use as my primary machines are a mid-2012 MacBook Pro Retina 15" (I bought it for the screen, my previous ThinkPads were QXGA builds, I wanted something worthy to replace them, it was the only option at the time), and a $60 Windows 8.1 tablet from Micro Center (the WinBook TW700).
As an aside, the interesting thing with Windows Me is that it wasn't actually as bad as people made it out to be... if you had an OEM preload. See, an OEM preload likely had all WDM drivers, and a lot of Me's stability issues were caused by mixing VxD and WDM drivers, as I understand. (I think this is also part of why there were reports that installing 98SE and upgrading to Me was more stable than just installing Me - it was easy to get a mixed VxD/WDM system if you clean-installed Me (which installed some WDM drivers), whereas an upgrade would end up with an all-VxD system.)