1) Roland EM-2000. I've bought this arranger keyboard more than 20 years ago. At that time I was more into performance and improvisation rather than composition and production and I've had a number of arrangers through the years. This particular one was quite expensive back in the day and one of the rare cases of me having a flagship instrument at the time. Unfortunately, it hasn't aged well and is one of the few pieces of equipment I have but I don't use anymore. I've tried to sell it a couple of times for a pittance but finally given up thinking about the original price I've once paid for it, so I've kept it out of nostalgic reasons.
2) Rode M5 Matched Pair. Though I primarily work with VI's and DI instruments, I would also like to be able to record some acoustic sources now and then. Since my current studio isn't soundproof, I rarely have the opportunity of absolute peace and quiet, so I didn't want to invest in some pricey microphones for the time being. Though M5's have decent reviews, I've never had much luck with them, especially when trying to record relatively quiet sources like fingerpicked classical and acoustic guitars, at least not when using audio interfaces which I have at my disposal.
3) Avid Mbox3. For a while, I've tried to stick with the most budget-friendly way of maintaining a Pro Tools rig, but after switching to REAPER and Focusrite interface I kind of regret this, even though third-gen Mbox series is (was) the best one, both regarding features and the actual quality.
4) M-AUDIO Axiom 49. I bought this more than ten years ago and I'm still using it along with my Studiologic SL 990 Pro as a MIDI keyboard controller of choice. It has everything one could potentially wish for, even aftertouch, but I often regret not buying a larger model for easier work with keyswiches. Also, the 2nd gen of Axiom shifted the sliders to the left which is IMO a good move, but alas you can't find it in stores anymore.