I made a lot of hardwood counter tops at my last job. Maple, cherry, poplar, white oak (flat, rifted and quarter sawn), Jatoba, red beech, bubinga, mahogony, walnut, wenge, and even one in zebra wood! Never teak though. White oak is a great and cheaper choice, good moisture resistance. Jatoba is real tough and handsome, cheaper than most exotics, and quite heavy. Mahogony is a real nice looking top, but its real soft...maybe not a good choice in a high traffic or high use environment.
Make sure to dry fit then remove your top, finish all 6 faces! They dont all have to be pretty like the show face, but I saw a lot of complaints on vanity tops (we sent them out raw) where the contractor installed, finished the top, ran like hell. They almost always warp/check or worse.
I love teak but I hate teak too. We used teak for flooring, exterior thresholds for beach homes, nosing. Teak is tough but absolutely sucks to work with. No fun at all. Smells like rotten artificial blueberries to me. It will eat all of your HSS cutters (jointer/planer) in a few lineal feet..never mind a few passes. Need carbide to work it. If you don't have carbide knives already add $275 for the planer and $140 for the jointer. Teak dust turns into bubble gum in a widebelt or drum sander, real mess to clean your machines afterwards. Doesn't go well with random orbital either. It will kill most hand tool steel quick. Plus the dust is toxic to most people, makes you wheeze quick. Difficult to glue as well. We used to whipe the edges with acetone, epoxy and clamp the hell out of it. I'm not a finisher but am told it doesn't take finishes well either. To top it off, it isn't particularly stable either in a high humidity enviroment. It doesn't take fastners well either (screws break, nails bend!)
On the up side its pretty, wears well, and seems to be popular for high end counters right now (they put one in the latest 'This Old House' project too! In one episode they showed the fabricator, beard covered in that sticky teak dust, no dust mask, pushing a PC speedmatic through a 2 1/2" thick teak slab with an giant ogee cutter that looked like a helicopter blade! I'm guessing he made the sink cutout with a chain saw?
I was thinking of making a morado counter..bolivian rosewood they call it. still tough to work though. Maybe undermount sink might help the water drain well?
If your committed to teak good luck, and check out this site:
http://www.smithandcompany.org/CPES/index.html. They sell ausome products for wet use/marine enviroments and restoration. Might be some useful products for any wood counter. I used their CPES on a T&G porch floor restoration on my house, made the Doug fir harden up like iron, also makes it mostly waterproof. Makes paint and varnish stick better too if you follow the finishing schedule they advise. They also have wet 2part epoxy for oily/exotic woods that works well.