Others have mentioned Moon's
Vatta's War and Harrison's
Stainless Steel Rat and
Deathworld trilogy; one might also want to throw in the second book of his
To the Stars trilogy,
Wheelworld. H. Beam Piper's Terro-Human Future History has had some books mentioned, most notably
Space Viking, but one could make interesting Traveller adventures out of
Four Day Planet or the Fuzzy saga (including the apocryphal books by William Tuning and Ardath Mayhar) as well.
Other places to look would be the John Grimes series by A. Bertram Chandler, and the Liaden Universe by Sharon Lee and Steve Miller - both series are available
in toto from Baen.
A little farther afield, but still worth thinking about, is
The Course of Empire and
The Crucible of Empire, the beginning of a series that is currently on hiatus, because one of the two authors, K.D. Wentworth, died suddenly and unexpectedly. (Co-author and Baen line editor for the Assiti Shards universe Eric Flint has plenty on his plate; there are indications of intent to pick up the series at some point in the future, but for now...

)
If you can get past the
Enterprise crew acting like the
Enterprise crew, there are some stories from the Pocket Books Star Trek novels that might be worthwhile sources for adventure ideas; two that immediately come to mind are
Uhura's Song and
The IDIC Epidemic, but there are others.
The thing to remember, though, is that everyone has a different idea of the answer to "What is
Traveller, and what is '
Traveller-like' fiction?", so you'll need to take anything said in this thread with a grain of salt - especially since I seem to take a slightly broader view of the question than is perhaps conventional...