Recently i've been having great fun with Altered Carbon (and the two sequels) by Richard Morgan, as well as the Gaunt's Ghosts and Horus Heresy Warhammer 40k books (despite not being into 40k otherwise bar the awesome rts)
Read the first "Kovaks" novel a month ago, great stuff. At some point, I will definatly get the other two books by Morgan.
Got to give props to my favorite author, Robert Silverberg. He ha been writing since the mid-60's, and has covered all astpects of the sci-fi genre, from space operas to intense, charecter driven novels. Two I would reccomend to anyone would be Dying Inside, the story of a middle aged man who can read everyones minds, and what happens when he slowly loses the power, and how and if he can transition to a new life without the ability.
The second is the Majipoor Trilogy(Lord Valentine's Castle, The Majipoor Chronicles, Valentine Pontifex), just awe inspiring scope, great reading.
Am currently working thour S.M. Stirling's ten book series of The Change, good post apopolyctic stuff. The core book, Dies the Fire, is incredible, and will entice any SF reader into the series.