Mmmm... Muscovado... That is a nice sugar for the style.
Shawn.
:lol: Shawn why do I get a mental picture of Ainsley Harriott with that statement?
Getting back to the original question from Tony all of the above should be good but I reckon half the fun is experimenting and seeing what you like.
For tripels any pale sugar is good, in other words plain old white table sugar, dextrose or even raw sugar. Dubbels would benefit from less sugar and more character from the specialty grains. NM's suggestion of Muscovado sounds really awesome. I've used it in a couple of British Ales and found it to be really nice and rummy.
My personal fave, though I can't lay claim to having delved in many sugars as others is Chinese Yellow Lump which is cheap and seems to work nicely in either pale or darker Belgians.
Like Shawn said it's more a case of avoiding the hotter Belgian fermentation byproducts in excess more than anything. Having used Wyeast 3787 I can say that this will occur if the yeast is handled badly (like I did with it).
Adding it to the secondary sounds a great idea. I've only done this once when I bought some brown Candi Crystals back from Europe several years ago and added them to a La Chouffe clone. Basically I primed the keg with the sugar component and bled the gas off until the secondary fermentation had subsided then forced carbed to get the correct carbonation level.
Seemed to give a smoother type of finish to a higher gravity Belgian.
Moreover Tony I reckon the biggest mistake (I've made personally) is attacking them way too early. Most stronger Belgians I've done (say over 6%) have benefitted from just sitting there in storage for at least 3 months.
BTW NM's experiences with sugars are valid. After having sampled his Gouden Carolus clone I was totally blown away. What a great example.
Warren -