Sara

Not sure what your last read was, but the "Masters of Rome" series by Colleen McCullough is fairly acclaimed here in Australia and it was my first fictitious foray in to the world of Rome during high school.

 I must admit, slightly shamefaced, that I've not read more than the second book. Though I'd say that speaks more to my penchant for apathy, rather than to the quality of writing.

I second the series by Colleen McCullough. They are absolutely fantastic. 

The Falco series by Lyndsay Davis, if you like detective fiction laced with laconic wit. Thoroughly researched and tons of fun - not all the books are set in Rome itself, but the majority of them are (there are maybe three or four that aren't, though they nearly all have scenes in Rome). They start with The Silver Pigs.