Actually as Alan Watts said in one of his talks, most contemporary philosophy is no longer about the big questions. Philosophers have sort of given up in favor of the scientific understanding of the universe, and the scientific methodology... and their careers.
If you are interested more in the "soteriological" aspect of philosophy, ie. when it's about finding peace of mind and answering the big questions... Greg Goode has a very nice site on the subject of "emptiness"
http://www.emptiness.co and has a few articles introducing Western philosophy works as a kind of bridge between Western thought and Eastern teachings.
http://www.emptiness.co/bestwesternbooks
I wrote to him last year asking about time and he also suggested Heidegger's "Being & Time" that IceCream mentioned. I haven't got around to reading it though. Back then I was into Alan Watts and found his talks very helpful and they really blew a hole through my rigid thinking. And I mean.. I was already fairly "open minded" but the irony is however I defined myself was very rigid. I still had (and have) a huge ego.
What you're looking for I think is realizations. The big questions don't need books to be answered, but they need a lot of intensity and honesty.
I had a realization a year or two ago about truth and meaning. It's probably explained in very fancy ways in philosophy, but the irony is that it struck me when I was in a period deeply involved in UFO and conspiracy sites.

It hit me as I was hunched over my keyboard at 3am in the glare of the computer screen, looking at a blurry black and white photo on a UFO site... and suddenly my heart started pounding really hard and I was really scared. In a brief moment I sort of realized (and I'm just trying to translate here), that as much as I didn't know with certainty if any of these things were true, it was the same for everything else! I felt like everything I knew was going to collapse. I didn't lose my mind... but that may have been a good thing, who knows.
A switch has flipped and ever since I lost interest in UFOs and crop circles and the new agey sites like RealitySandwich, but not because they are "not true", but because it became clear that nothing else is true either.
It's a big relief to no longer feel like I have to check bullets on a long list of things to do to have a meaningful life... but as I found out it's just one realization, and the search is not over. And as undead_saif said it could leave you in an interesting ... but disconcerting place.. depending what realizations you had.
Just be very careful when reading "nihilism". You might read into it what you want to read, rather than what the author tried to convey. It could be argued to be the same for all philosophy writings but when it's about meaningless existence and such, it can be deceiving. I find that having some meditation experience or a Vipassana retreat is very helpful because when you lose heart, you have a new medicine.. you come back to what is.. your breath or whatever.
Like Henry Rollins said.. a hundred pounds is a hundred pounds. It never lies to you. :p