i dont think any normals leds run off of AC power and 200 ma isnt going to light up very bright.
the size of the led is not only for the intensity of lighting but also for the penetration. there are no optics that i know of for the small 5mm leds. when youre talking about the more powerful 3w+ leds they usually have some kind of focusing available that you can buy seperateley, which you need if your tank is deeper than 12-18 inches.
if youre looking to use leds to light a fish only tank, id say save your money
for plants its kinda a waste because you dont need the immense amount of light and theyre expensive to start out on.
if you insist though, read on
when are deciding on how many leds you need for a tank, you have to realize that there is no hard and fast watts per gallon rule, and especially not with leds.
for the area that an led covers (small radius, about 3 inches) the light will generally be at least equivilant to 70w of metal halide, unless it is too deep without optics(12 in)
which is more than enough for plants, id say you would have to dim them which some drivers will allow or just get weaker drivers.
you wanna put an led about every 3 inches or so, if your tank is shallow and you dont need optics, if you do, then do a little trig and figure out how much area its gonna cover with the optics that you are gonna use.
my led build costed about 250 for 18 leds
heatsink 50 bucks ( i could have cut this cost a little knowing what i know today)
drivers 60 bucks
leds 5-6 dollars each so about 90 bucks
power supply 15 bucks
other misc supplies and such was about the rest of the money
if you build your own drivers you can save a bunch but it does take some eletrical knowledge.
you also need a soldering iron and a drill press/ tapping handle and bits unless you are going with thermal adhesives.
that being said, the two leds to use are either cree xp-g ( newer, more powerful) or cree xr-e ( older but still good)
luxeon rebels can crank as much light as the xr-e but use more power, plus they will pass current through to the heatsink so you have to use some kind of insulating compound.
larger leds like the mc-e are going to spotlight the tank because each one is like ten watts and same goes for triple leds and other high power leds.