You **certainly** without reservation want to start with the amp first!
The reason is simple: you might have a preference for a certain kind of amp, for example, tube or solid state. Maybe you've heard how much better an amp can be if it lacks feedback. That sort of thing.
If you start with the speaker first, you may be painted into a very expensive corner. Here are some examples:
If you start with the Sound Labs because you fell in love with the speed, delicacy, bandwidth and sheer convincing qualities those speakers have in spades, you're screwed if you also only will deal with solid state. You will never get the performance out of that speaker! The speaker has a 30 ohm peak in the bass which is easy for a tube amp and hard for a solid state amp (IOW overall weak power with weak bass). At the other end of the range, the speaker is pretty low impedance (1.5 to 3 ohms depending on the position of the Brilliance control) which will cause most solid state amps to be too bright and nothing for it but to turn down the Brilliance control and deal. This is the case with most ESLs BTW.
If you happen to prefer tube sound, you will have a very difficult row to hoe if you get Magnaplanars. That speaker is very revealing, and there are only a handful of large tube amps that really make the bandwidth and power that are both needed for that speaker to sound right.
I can go on, but the point is very obvious- its a foolish act to get a speaker first and then discover that its incompatible with the type of amplification you prefer. You'll have to start all over again, which sucks.
