Both Z2300 & AL MX5021 were best in 2.1 segment.
As for A5, i am surprised people are bringing them in comparison with 2.1 speakers.
A5 are studio quality 2.0 monitors. Obviously, their sound quality will surpass most of the speakers mentioned here. Intended for professional use generally.
Now, dont think they'll blast or rattle the walls like MX5021 / Z2300!

Their spatial arrangement could be of issue to many. Plus, not to mention the lack of ".1" i.e. woofer unit. A5s are strictly built for testing music frequencies and quality purposes.
2.1 systems on the other hand serve overall purpose. May it be music, videos or games!
And yes, 2.1 systems do have better power distribution across channels in comparison to 2.0 systems. Corsair SP2500, AL MX5021, Logitech Z623 power ratings easily surpass A5 ratings, thereby making them excellent choice for home/casual use.
As for the best of 2.1 speakers, I can't help but suggest these:
Cambridge Soundworks MicroWorksII & Corsair SP2500.