Also consider Presonus Studio One Pro. The community is very active, and they're coming out with version 2.0 this fall. The program was written by some of the top programers formerly with Steinberg. I used to use Pro Tools, but since I also use a ton of virtual instruments I found the work flow in this program much much easier. It supports through VST3. It's not cheap, but then I also think you get what you pay for, usually.
The KRK Rokit5s are good, but I really would look at maybe the Rokit8s. The reason is that there are typically some mud frequencies around 45 Hz that can overwhelm a mix. The 8s will get you lower than that down to 44 @ -1.5 dB, but will probably go to 40 at -3 or -4. That's about 1/3 octave. The 5s cut off around 52 Hz. The monitors I currently use do fine from 63 - 20 kHz, and I found I need to buy a subwoofer because I can't hear what is going on below about 55 Hz and before I was aware of this I would boost the bass up, only to find it was muddy on other systems that were capable of handling the bass. Bass became guess-work. So I'd consider the Rokit8s.