It's my own humble opinion that Wiliam C. Dietz is one of the very few modern authors continuing the grand tradition of pulp style action and adventure sci-fi.
He's written many novels since War World (Galactic Bounty) was first published back in 1984.
He basically writes good old fashioned sci-fi adventure, with plenty of action and often with monsters/aliens thrown in for good measure. Easy to read and loads of fun. Always a pleasent way to spend a couple of hours.
This is the link direct to his website and complete book list.