There are so many, I would like the most detailed result I can get.
This is going to be interesting.
It depends how deep your pockets are ...
The two basic tests I'd recommend are Ancestry DNA and Living DNA.
Living DNA gives a more detailed UK and Ireland based ancestry result whereas Ancestry DNA gives a better wider picture and is good if you are looking for matches with a paper-based family tree. Living DNA will give you a maternal and paternal Haplogroup (maternal only for females) whereas Ancestry DNA will not. Living DNA are introducing a new matching service and are currently accepting free transfers of Ancestry DNA raw data. Ancestry DNA have by far the largest database (which is good if you're interested on matches) and also have a sale on at the moment (you will need to be a member of their subscription service and have a linked tree to get all of the benefits of this test). Both sets of results can also be uploaded to sites that specialise in health-based reports (such as Promethease).
Both Living DNA and Ancestry DNA raw data can be uploaded to other sites either for free (such as Gedmatch) or at cost (such as DNA Tribes) for alternative analysis. There are also a number of reports that can be ordered (very cheaply) from a few individuals who specialise in analysing your DNA against publicly available samples. These guys have a very good reputation for the work they do.
There are a few more tests available:
Family Tree DNA (FTDNA): This is good if you want to go deeper into matching with relatives around the globe and can give some very accurate maternal and paternal DNA Haplogroups. It isn't cheap though and this level of detail will cost several hundreds of pounds. Ancestry DNA raw data can be uploaded to this site for free and a basic analysis of this can be had for a small price. You will need to do a separate test with FTDNA if you want to purchase any more detailed tests though.
23andMe: Pretty basic Haplogroup analysis (the tree they use is somewhat out-of-date). The ancestry report is generally pretty good (and can be improved if you have a close relative who has also tested there). 23andMe will also provide health-related results at a cost.
My Heritage: The ancestry results are, in my experience, not as accurate as they could be and there is a membership cost attached if you want top link your DNA to a sizeable family tree (i.e. over 250 people). They will accept raw DNA data from Ancestry DNA, FTDNa and 23andMe for free and also provide a DNA testing service from scratch (using FTDNA's laboratory). The price for this is very reasonable, however, the last I read was that you need to have a membership subscription to get the full functionality of this test.
24 Genetics: The ancestry results are okay, but they are missing a number of samples to compare your DNA against (especially in the case of some parts of Ireland). This should improve in the future as more samples become available. They also offer health-related results. They offer a DNA testing process from scratch and theiir prices are currently more expensive than some of the other companies at the current time.
Gene Plaza: Great site and the ability to upload Ancestry data is useful. They also provide a DNA testing service from scratch and their prices are more expensive than some of their competitors.
DNA Land: Very basic results. They offer free raw data uploads from Ancestry DNA, FTDNA, 23andMe and My Heritage.
GPS Origins: Very basic results with some very strange conclusions. They also offer a DNA testing service from scratch. Again, the price for this seems quite high. I would not recommend this test.
Full Genomes Corporation (FGC): This company specialises in male DNA and whole genome DNA analysis and currently produce the deepest results available on the market. They are not cheap though. Expect to pay anywhere from a several hundred pounds to a couple of thousand pounds if you want the best cutting edge results.
YSEQ: This company offers advanced testing which is similar to some of the specialist tests offered by FTDNA and FGC. They are useful if you want a cheap means of digging deeper into a basic paternal Haplogroup provided by Living DNA or 23and Me.
The information above is based upon my own use of these services (either in part or in full) and like everything else YMMV applies to DNA analysis as much as it does to shaving.