At the outset there is no such thing as best speakers. The important point is speakers that is good (or best) for your ears
There are a number of considerations that have to be taken into account.
1. Price of course. Speakers follow the rule of diminishing returns. As you start paying more, the additional value you get from the speakers start going down. Beyond a certain level, additional money do not add any value.
2. The important marriage between the amp and the speakers. You can go two ways. You can decide on the amp based upon specification and reviews. Then, you can buy speakers that fit the amp well. Alternatively, based upon certain considerations you can pick a set of speakers first, and then find the amp that fit the speakers best.
The way to do this is again two. One is to to visit the houses of friend and relatives who have HT installed and listen to their systems. As other have suggested you can also visit the houses of HFV members in your city with their permission. The other way is to visit a few reputed dealers and request them to mix and match speakers and amplifiers and list to various combinations.
3. Your listening habits. This is very critical, and that is why I always advise people to audition, audition, and audition. Yesterday in a small meeting of members, we were discussing my personal likes and dislikes on the question of a two channel amp. During the discussion I realised that I like low frequency sound to be tight and taught. That narrowed down the choices of my amp quiet drastically.
In HT, what are your likes and dislikes? Do you want deep and boomy sound? Do you want subdued highs? Do you want dialogues to be be clear, audible, and understandable?
If you like the highs to be subdued, look for British/Canadian speakers such as Epos, B&W, QA, PSB, etc. If you like high sounds, look for US speakers such as Martin Logan, Deftech, etc.
If you are little adventurous, you can look for ribbon and planar speakers from companies such as Magnepan, Martin Logan and others. These would certainly need powerful sub woofer(s) as they stop at 100 to 150 watts irrespective of their specifications.
Last but not least is the type of speakers you can fit into the room - floor standing, bookshelves, in-wall of on-wall?
If money is not a consideration, I would suggest you spend some money on room acoustics that will solve over 75% of most HT room issues.
The issues are many, and a person who makes a list and narrows down his choices will be a happy one.
Choose carefully.
Cheers