Fusion is the style I’m finding my ears drawn to these days.  I was reading up on it the other day on Allmusic.com – very interesting –

The word Fusion has been so liberally used since the late ’60s that it’s become almost meaningless. Fusion’s original definition was best: a mixture of jazz improvisation with the power and rhythms of rock. Up until around 1967, the worlds of jazz and rock were nearly completely separate. But as rock became more creative and its musicianship improved, and as some in the jazz world became bored with hard bop and did not want to play strictly avant-garde music, the two different idioms began to trade ideas and occasionally combine forces. By the early ’70s, fusion had its own separate identity as a creative jazz style (although snubbed by many purists) and such major groups as Return to Forever, Weather Report, the Mahavishnu Orchestra, and Miles Davis’ various bands were playing high-quality fusion that mixed some of the best qualities of jazz and rock. Unfortunately, as it became a money-maker and as rock declined artistically from the mid-’70s on, much of what was labeled fusion was actually a combination of jazz with easy-listening pop music and lightweight R&B. The promise of fusion went unfulfilled to an extent, although it continued to exist in groups such as Tribal Tech and Chick Corea’s Elektric Band”.
What this leaves out, however, are the strains of fusion found within progressive rock.  The explanation above omits the other side of the coin – the sounds that came forth when ROCK musicians started to play JAZZ.  Their were some magnificent fusion bands that swung heavily to the progressive rock end of the musical spectrum, as opposed to the jazz-rooted musicians playing rock.
Nucleus hit a high water mark with their collision of progressive rock and jazz “We’ll Talk About it Later”.  Superb album by a genuine progfusion progenitor.
The Soft Machine’s Third album is another prime example.  This is obviously a progressive rock band playing jazz.  It sounds great.
More great prog fusion bands followed.  Iceberg from Spain comes to mind.  Sammla Mammas Manna from Sweden put out a few high quality very original albums featuring their take on fusion.  Czech Republic saw some prog fusion pioneers in Fermata, Jazz Q, and Blue Effect.
To me, progressive fusion is more exciting than jazz fusion, primarily because the music sounds more exciting.