I'm tempted to pick up my first tenkeyless, but strictly speaking, I don't need it.
I have the Filco Majestouch Tactile Touch "Otaku" NKRO (in @ EK for warranty service), ABS M1 (stolen by my father), a Filco Majestouch Tactile Touch (stolen by my brother), a Rosewill RK-9000 (currently using), and a BlackWidow (currently in the living room).
So mentally (a.k.a., me tricking myself) I only have two keyboards (since that's all that I have in front of me). However if I want an experimental board I might was well pick up a Topre tenkeyless, but then I'm making two changes at once (Torpe switches/form factor). I could hate the tenkeyless or the topre switch and then hate the board as a whole.
Also, the budget only permits one, and the Topre would be a stretch, so don't recommend both.