BX5a vs. BX5a Deluxe
The main difference can be read here:
M-AUDIO - Studiophile BX5a - 70 Watt Bi-Amplified Studio Reference MonitorsM-AUDIO - Studiophile BX5a Deluxe - 70-watt Bi-amplified Studio Reference Monitors
"The Studiophile BX5a Deluxe monitors update the best-selling M-Audio BX5a system with a variety of enhancements. The updated waveguide delivers excellent imaging. A new low-frequency transducer provides well-defined bass. Custom amplifier tuning enhances the integration between the high and low frequencies, delivering refined spectral balance and a smoother response. An elegant new industrial design completes the package."
I think in a category like this it is very hard to recognize any kind of slight difference with your ear. (It's not a change from Bx5a to Adam A7).
Both should serve a home-studio very well! If you have money, go for the newest.
Furthermore, look at this video...
YouTube - BT - This Binary Universe Interview from M-Audio
I know it's a commercial, but if these "older" monitors were good for mixing an orchestral-electronic album like "This Binary Universe", should be good for you too. And if you want real bass imaging, buy a BX10s as well. I think is a cost-effective 2.1 studio monitor set (real monitors in every sense of the word) for your home, than a much more expensive pair of monitors, even if they had better sound (but you can't afford it).