You will find it in a whole lot of trappist beers (Westmalle) and abbey beers.
But there is no general category Belgian beers. We have
- The trappist beers
- Blonde tripels
- (Relatively) light and strong dark beers
- A whole lot of abbey beers
- Speciale Belge, or Belgian Pale Ale
- Saisons of course
- Lambic and gueuze, and the derived fruit beers
- The strong blond beers like Duvel, Omer and Filou
- and then we have a whole lot of new brewers who go crazy (Brussels Beer Project is very create, or 'T Verzet, White Pony Microbrewery)
- Beers like Kasteel Donker, Gouden Carolus and Straffe Hendrik
The banana you will find it actually more in blond beers. The dark beers seem to have it less.
My personal favorites: Westmalle Tripel, WV12, St.-Bernardus Tripel and Abt 12, Rochefort 8 and 10, Kasteel Donker, Martha Brown Eyes.
Since a couple of years I ferment my abbey/trappist style beers open (covered by cheese cloth), and I underpitch a little bit (0.65 instead of minimum 0.75). Except for placing my fermentation vessel in a room with a relatively stable temperature, I don't do any temperature control.