Admittedly a bit lost

Folks

I am a long time music lover who is dipping his toes into high end audio for the first time. I have long enjoyed high quality headphones (Sennheiser HD650) and earphones (Etymotics all the time) but have not spent the big bucks (that I don't have) for high-end equipment. :)

However, I have recently acquired a Jolida tube amp (40W output) and am looking for good speakers to pair with them. I intend to go around listening to a bunch of speakers but I need to at least narrow down what sort I should ask my local dealers to have available for me to try. That is what this thread is about.

My constraints are thus:
- My musical tastes run the gamut from classical choral pieces (Bach's cantatas and mass, Arvo Part, Hilliard Ensemble's works etc - i.e. all mid-range frequencies) to experimental electronic music (Autechre, Aphex Twin, Flying Lotus etc - i.e. deep sub-bass and full-frequency spread music with absolutely zero traditional instruments and every sound is synthesized).
- My amp is a 40W tube amp
- I live in an apartment and so listen at volumes ranging from low to moderate.
- My budget for speakers is about $3K (slightly flexible).

With those constraints, my dilemma is that I don't know if I should be trying out high-efficiency speakers or low-efficiency ones? Should I look for 8ohm speakers or 4ohm ones? Something tells me that with low power tube amps, I should be looking at a high efficiency low impedence speaker. However, will that sort of speaker be able to navigate the high speed bass attack of electronic music when driven by an amplifier such as mine?

I am not sure where to begin, so I would really like some advise from folks here. Thank you so much!