Skimmed the thread and didn't see anything about the Baen Free Library. Over 100 books available online for free
I've read:
1632 (Eric Flint) / 1633 (Eric Flint and David Weber) (and have a couple more books in the series) - I liked them, but each book after 1632 is a collaborative work with a different co-author, so be prepared for the style to change drastically from book to book. I got through 1634: The Ram Rebellion but couldn't motivate myself to finish 1634: The Galileo Affair.
A Hymn Before Battle (John Ringo) - I got through it but haven't had the energy to go after the sequel yet.
On Basilisk Station and The Honor of the Queen (Weber) - I love this series, and just finished book 3, awaiting more books' arrivals.
Neptune Crossing, Strange Attractors, and The Infinite Sea (Jeffrey Carver) - The ultimate tease, book four in this series (Sunborn) was due out in 2001, but kept getting pushed back while Carver finished Eternity's End. Book four is now FINALLY out and available for free for a limited time on Carver's website (along with the aforementioned Eternity's End) at starrigger.net. I bought the first four books as a freshman in high school (in 2000!) and have been waiting for Sunborn for nine years now - just have to reread the first three to get back into the series. (Maybe I'm beginning to understand how Davey Jones felt about Episode III in the Do Over series? )
Mutineer's Moon (Weber) is the first book in one of my favorite trilogies ever.