There's a lot of talk about what kind of coalition might be "legitimate" with a lot of the tory press asserting that (a) the party with the largest number of seats should get first shot at forming a coalition and (b) the current incumbent should also get first shot (they will shout this second even louder if Labour get more seats)
This is deliberately spreading an utter misunderstanding of how government works. If a number of smaller parties have enough in common to work together and enough reason to oppose the biggest party, then that biggest party being in opposition IS the democratic will of the people.
article being a bit more eloquent about this
As for (b) - Gordon Brown did not get first stab at forming a coalition 5 years ago and the tory press were howling for him to vacate downing street despite the fact that coalition negotiations were still ongoing. Funny that.