I have a few that I would recommend.
*Select MoistureCover Concealers by MAC cosmetics:
They cover incredibly good and it moisturizes at the same time. Great for dry to normal skin.
http://www.maccosmetics.com/product/spp.tmpl?CATEGORY_ID=CAT157&PRODUCT_ID=964
*Maybelline Mineral Power Concealer
It's mineral based and it covers blemishes, scars, undereye circles, everything! The only con is that it doesn't come in a wide variety of colors.
http://www.maybelline.com/Product/Face/concealer/mineral-power-natural-perfecting-concealer.htm
*ANY Almay concealers.
They all work great, cover great, and they do what they say they will do.
Some will heal your blemishes while concealing them, some will moisturize your skin while concealing imperfections and there are even some made especially for dark circles. This is probably my favorite line of concealers.
http://www.almay.com/pg/main/catsub.aspx?catid=31&catnm=Face&subid=229&subnm=Concealer&nav=products
**I'd also go here for reviews of any other concealers or makeup products (eyeliners, foundations, eyelashes, mascaras, bronzers...etc)
http://makeupalley.com/product
I would recommend any Almay cream concealer for drugstore, and any Bobbi Brown or Clinique cream concealer for high end makeup.
Some of the top rated eye concealer products come from companies such as Revlon and Elle. There are also some other highly rated eye concealer products such as Olay.
Hard Candy Concealer
studio fix concealer!
It is incredibly difficult to determine which concealer of the thousands on the market is the best for a face with freckles. Some good ones include The Body Shop's Ultra Smooth Liquid Concealer and Boi - ing by Benefit Cosmetics.
Mary Kay markets a very wonderful formula of concealer for your situation that does not flake. Another good option would be to use Maybelline brand concealer.
Lancome concealer is special because it claims to be one of the most effective cosmetic concealers on the market. It is sold in most department stores such as Sears and the Bay.
Avon
maybelline makes AMAZING concealers especially dream lumi touch highlight concealer. covergirl does ,too
For dark spots, you need a yellow based concealer. This will give the best overall coverage.
Concealer or powder.
concealer
try Maybeline's concealer
I have combination skin and I get blemishes in my T-zone and need to use concealer every day. The best full-coverage concealer is probably the MAC studio effects concealer, because its so thick but light and gives a really nice heavy coverage so it hides all redness and dark spots. For just a cheap, everyday concealer is the Maybelline NY dream mousse concealer, because its super light and airy and has quite excellent coverage. For under the eye concealer, the best is Bobbi Brown, but just for a cheap drugstore one, the Physicians Fomula stick concealer or The Body Shop tea tree concealer stick are both good.
I have found that Signature Club A has a great line of concealers that cover nicely without feeling heavy. My personal favorite is the mauve concealer but i also like the yellow.
Best concealer for dark circles is the Tarte Shape Tape Full Coverage Concealer, which smooths and brightens the under-eyes while simultaneously blurring the appearance of fine lines and wrinkles or also the best shade of concealer that hides the darks circles is orange family in my opinion Since dark circles are primarily blue, reach for shades in the orange family. If you have light or fair skin, use a more peachy color. If you are more in the light to medium skin tone range, look for a bisque color corrector. If you have a dark skin tone, reach for an orange-based concealer