I would add "Pour autant que je sache" to the possible equivalents of "As far as I know".
Some people could opt to omit the "pour", although to me it sounds a bit more formal.
As far as I know, the 64-bit version is not yet available.
Pour autant que je sache, la version 64-bits n'est pas encore disponible.
My life, as far as I know, is far from over !
Ma vie, autant que je sache, est loin d'être terminée !
There's also a related form of "il me semble que", which is "semble-t-il". It can be thought more or less as a translation of "it seems".
Few people, it seems, are brave enough to...
Peu de gens, semble-t-il, sont suffisamment courageux pour...
I also personally use it to begin sentences :
It seems that they already got married.
Semble-t-il qu'ils se soient déjà marriés.
In this case, it is a bit more detached than "Il me semble que" : it puts on emphasis on the fact and enounces it as more of a general "truth" rather than your personal knowledge.
There's also a last one which I am particularly fond of, and which seems quite old, and that is "m'est avis que". It is a bit familiar so use it as an oral-only construction.
In my opinion, the facebook stock is grossly overvalued.
M'est avis que les actions facebook sont largement surévaluées.