The general trend on 24's is front disk, and either hs33 or disk on the rear.
On my zoot I have an Avid Elixr on the front (which isnt ideal, but it does the job)
You would obviously have to have the front wheel re-laced to a disk hub, but that would be worth it!
http://www.tartybikes.co.uk/disc_brakes/avid_bb7_09/c12p10083.html that would be more than adequate as well.
V brake on the back, as long as you get some good pads and V brake arms it will be perfect.
something like this would do perfectly http://www.tartybikes.co.uk/vbrake_calipers/shimano_acera/c109p10985.html
You also have the choice of using a V brake Evo kit, so you can fit a HS33. But these can be flexy, and probably worse than a well set up V brake.
Hope this helps a bit.