Hi Rex

When an expert is asked to comment on whether a sentence is correct, it is more polite or less dogmatic to use
would when a recommendation is made -- especially if there is more than one possible way to write/say
something correctly. So you might also think of would being used this way: 
"(If I were you,) I would write the sentence this way." 

Someone who is offering a correction or a better way to write something might also say:
"You can/could write it this way."

That means the person expects you to be able to correct the error now (and in the future).
----------------------------

In your two sentences above, the first one sounds like you are either making the decision to buy the router
at this moment OR you are promising someone that you will buy a router.

Without any other context, your second sentence sounds like you are giving someone a recommendation
to buy a Linksys router.  (i.e. If I were you, I would buy a Linksys router.)

If you want to say that 'it is possible, but not certain that you will buy a Linksys router', you could say this:
I might buy a Linksys router.


EDIT:
I see that GG and I answered at exactly the same time.   My comments are right in line with hers.