Now the tougher question is, how to choose between them. I have read a lot about this on the internet, and seems like the general direction is that we need to "hear" these side by side to say which one is better. Practically speaking this is not easily possible (atleast I am not aware of any stores that carry all these products).
As a novice in this field, is there a sure shot decision that gets me atleast 90% of a decent home theatre speaker system ?
First a question - How big is your room. I ask because 7.1 is simply inappropriate for smaller rooms.
But to your quandary above:
It is a difficult proposition (and even more difficult if you live in a rural area) to audition speakers. Fortunately Internet Direct companies do offer some help on this count. For example, Aperion will actually pay return shipping and give you a full refund if you don't like their system, so it is free to try.
It is more typical to have to pay return shipping out of pocket.
One of the local audio shops in my area allowed me to buy a pair of speakers (they were open-box or showroom demo's) and return them with-in a week for a full refund. A couple of others were game to let me carry a pair of speakers into their shop and set them up for A-B comparisons. From a practical standpoint you should work with bookshelf models whenever possible. Most systems use the same drivers in their bookshelves as in their towers and at you price point, BS speakers will generally offer better sound quality.
In any case, you should start with a receiver and sub which will be permanent components of your system, then start auditioning pairs of speakers (ideally in your room and in a 2.1 configuration) to find your sound.
I would expect most ID companies to extend any package discount to you if you trialed a pair of speakers before committing to a 5 or 7 speaker package. Just explain what you are doing and ask up front (I'd ask by phone, but request a statement via email).
If you trial a pair of speakers and post what you do and don't like about them, you will get some good suggestions on which other speakers might be a better fit.
If you are not willing to invest the time and effort:
1) If you are not worried about looks, the Behringer 2030P's mentioned earlier are truly good speakers at an incredible price (which would give you more for your sub). They are made to be studio monitors and are sold by pro audio shops (that is guitar-amp-keyboard shops).
2) For more, but still in your budget are the Ascend CBM-170's (you could mix in 3 CBM-340's across the front depending on your sub budget).
From my observation, the two above speakers (Behringer 2030P and Ascend 170/340) are more recommended with less controversy than any others by members of this forum as speakers representing excellent value for their performance/cost.
HTH