There are two choices that amount to one:

Libs support Labour. Majority paper thin assuming SDLP/ Alliance/ Green/ Plaid/ Scot Nats support Labour and DUP support Tories. Coalition will break up on budget.

Libs support Tories. Majority of about a hundred, fairly secure, but coalition breaks up on budget.

The best the Libs can hope for is to force through some electoral reform as part of a deal, but it's unlikely that any coalition will be stable enough to see it into law.

If we'd had full PR (seats allocated according to vote share), the result might have looked something like (using figures from mid- afternoon):

Con   234
Lab   185
Lib   148
SNP    12
DUP    5
UKIP   20
BNP    11
Green   6
Plaid   5
Sinn F 4
SDLP    3
Alli    1
UCUNF   3
Trad U 1

And, perhaps oddly, the result would have been very similar if the regions England, Scotland, Wales and NI had counted their proportions separately, though NI would have been less well represented overall.

It seems that in this case, all else being equal, the Liberals could have chosen a stable coalition with either party, and the presence of the extreme nutters would have been annoying and distasteful, but little more.