EMG 40DC

First of all, if you are deliberating between active & passive pickups, there is little doubt on most of the Bass forums that the consensus is overwhelmingly in favour of Active EMGs. Even if you don't have a battery recess in your bass, the 9V battery can easily be accommodated inside a standard tone pot cavity. I did this with my Peavey Grind 5 string, simply purchased a plastic 9V battery holder from Ebay, then epoxied it to the inside of Tone pot cavity cover.
Its firmly in place and does not interfere with the pots.
But the sound... its fantastic. Replacing the indifferent pickups in the Peavey with a pair of 40DC's was the best upgrade I ever made, the range of tones, clarity, sensitivity and quietness, you can't really beat these, without spending 300 or more Euros on boutique electronics..
I play metal, doom and technical death varieties, the low end growl I get now is priceless! Also, the solderless electroncs system and pot set is just another reason I love these pickups! Its all included and was a joy to set them up. Only one thing! They require weird US sized nobs, the two tiered, `Babel' style - single barrel nobs wont fit -

I upgraded the pickups on my Ibanez SR305EB with the EMG 45s, hell of a difference. Just be aware, on the majority of Ibanez bass guitars you will need to resize the pickup cavities.

Another thing worth mentioning is you will want to buy the EMG ABC system too if you like playing both pickups at the same time. You can run a 2 vol knob configuration, but it's way easier to setup with the ABC.