Go Active Crossover or Upgrade existing XOs?

I don't know why active loudspeakers haven't caught on in the consumer market, but there are many examples in recording studios. I have some active Genelec monitors which sound great as nearfields although they won't be to everyone's taste. 
Technically the benefits are compelling, but I understand why people might be sceptical given the enormous amount of BS in the audiophile world. Siegfried Linkwitz' LXmini speakers can be paired with Nelson Pass designed active crossovers... admittedly not that mainstream but I'm yet to read a bad review - and they're designed by two people with some 'audiophile' kudos.
I agree with @erik_squires that active crossover design isn't that intuitive but it really isn't much more difficult than passive as long as you don't try to iron the frequency response completely flat with endless filters.
If you're starting from scratch then it would probably be best to reverse engineer the existing crossover (or get someone to do that for you) and model it in DSP to use as a starting point. You can then make adjustments in software before re-creating the filters using analogue components (or getting someone to do that).

I'll go with Eric on this one. Digital cross overs is absolutely the way to go especially if all your sources are digital. We can argue about analog later.
You can do almost anything you want in the digital world without distortion. Using digital cross overs and multiple amplifiers makes the most sense if you are making your own speakers. It gives you total control of the situation and if you have a good room control system you can measure the results. Millercarbon you are wrong here. Many manufacturers give you the opportunity to bi amp. Magnepan and Wilson do this. The famous Levinson HQD system was tri amped. 
Gadios, It all depends how you do it. Implementation is everything and it will cost you some money. It is possible you might be better off just getting new speakers. If you like playing around and experimenting great but, if you have not got a way to test what you are doing you might wind up out to sea without a compass. If you like your speakers you might consider getting a new amplifier. 

I agree with @erik_squires that active crossover design isn't that intuitive but it really isn't much more difficult than passive

And passive crossovers are difficult to do right!  :D That was kind of my point.

Yep... difficult to design but not that difficult to copy.

Anything is possible with money and time.  But then with too much money and time will lead to hubris.  And that's why God created men and women.  

OK, enough hubris from me.