I would go with active-speakers, here are two mid-price range options;
KRK RP6 RoKit G2 – Thomann UK Cyberstore
and
Yamaha HS80M – Thomann UK Cyberstore this could be bought with an additional sub Yamaha HS10W – Thomann UK Cyberstore
I got the yamaha w/sub set my self and they sound very neutral, almost to the boring but thats what you want in music production is to get a sound that you know where things are in the whole sound picture and it sounds good on most speakers. Too good sounding speakers makes no good monitors….
I got friends that have bought the KRK ones, they sound better(at parties) maybe but its not as neutral as Yamaha, the Yamaha’ have some possibilities to use the switches on the back to make more them hi-fi sounding for the occasion. I always think that two way speakers need a sub additional. There is always some stress about a bass unit that need to go too wide in the freq. spectre…but thats a matter of opinion, most people do not have a sub so for music production it might be too much, considering you want a decent sound on all kind of equipments.