The Cicero one is very, very good. I have several of his books but this is the best one. His biography of Augustus is interesting in a lot of ways but simply feels a bit flat after this. I also have his book about Hadrian but haven't had a chance to read it yet. I'm hoping he'll write one about Anthony who really deserves an objective treatment that covers more than the last few years of his life but, well, sex and madness sells and the focus is probably always going to be on Cleopatra's role in the final events.
I agree that there is a lot of poor Roman history on the net, but a very good resource is to be found at
UNRV.com. It is frequented by many Roman history academics (and several well known writers on the subject) as well as normal people with an interest and it's forums cover virtually every aspect of Roman history.