Well, cutting all the tech-jags, i would just come to point.
RMS stands for "Root Mean Square". 50 RMS indicates the true power of the speaker amplifier, which is a fancy mathematical formulation for certifying the average amount of power an amplifier can continuously produce, no matter whats ur volume level is! Plus, the better is RMS rating, better are the speakers! Simple as it gets.
Regarding, Inspire 2.1 or X230, trust me...i've seen them performing. They stand no where close to MMS430!!
And yeah, ATP3 was one good set.
Ok, Megaworks 250D is one of the finest 2.1 set i've seen these years. Just skip B&W or Sony though...
250D boasts pure 250W of power rating. And the speakers are THX certified. That means, the price tag is ofcourse high.
Last time i asked, the price was ~12k ! Anyways, the speakers are overkill for most of the setups out there.
Ohh..i remember one more giant. Altec Lansing 621! Actually, had its Papa with me...i.e. 641 !!

Excellent set with right set of drivers. Though, the price was an overkill here as well...~7-8K ! Boasts ~113W of RMS.
See, imo philips set has best vfm! Ok, here are some others as well...
1. Sony SRS-D211! They have 32W in total. Priced accordingly~4-4.5K ! MMS430 should be available for just 2.2-2.5K!
2. Logitech Z-4! Quite a good set, i would prefer over MMS430. Priced ~ 5-6.5K! Check the availability too.