The Kingkiller Chronicles by Patrick Rothfuss
-Follow the life of Kvothe, a young musician and arcanist, as he struggles to overcome poverty, learn the history of the mystical "Chandrian", and learn who he really is. Currently only two books of this series are out, but they are both awesome reads. Starts with "The Name of The Wind"
A Song of Ice and Fire series by George R.R. Martin
-A series of political intrigue set in a fictional feudal society. Tons of political alliances and betrayals. Not a series you can just skim through, but undoubtedly one of the best fantasy series out there. Starts with "A Game Of Thrones". Currently unfinished, with 5 out of 7 books released.
Waylander by David Gemmell
-a deadly assassin finds out what his true character holds when he finds the fate of a great many innocent people depending on his actions.
The Mistborn Trilogy by Brandon Sanderson
-A subjugated people rise up against the all powerful government of the time, takes a very intersting take on magic, one gains powers by "burning" metals that they ingest. Different metals give different strengths, and people can only "burn" certain metals. Starts with "The Final Empire".
The Dark Elf Trilogy by R.A. Salvatore
-A drow elf (dark elf) growing up in a world of evil and his struggle to remain uncorrupted by the evils of society. Starts with "Homeland".
Enders Game by Orson Scott Card
-Humanity's struggle against the "Bugger" aliens lies in the hands of a young boy named Ender.
The Worldwar Series by Harry Turtledove
-Reptilian aliens invade during WWII, humanity bands together to fight against them, takes the technology and political situations of the times into account very well. Starts with "In the Balance".
Emperor Series by Conn Iggulden
-Fictional story incorporating the lives of Brutus and Julius Caesar, incorporating a lot of the key events from their lives. Starts with "The Gates of Rome".
The Dresden files by Jim Butcher
-a wizard publicizes himself in the yellowpages as a Wizard in Chicago, a very good series. Starts with "Storm Front".
If anyone has something to add to these descriptions, feel free. That's just what I think of when I remember each of these series.