It really depends on what you want to make, I like buckwheat alot and it works well in an acerglyn thats going to be oak aged and I am working on an irish stout recipe that I will be using buckwheat for. early season harvest is usually lighter and good, late season is where you get the darker honey with deeper flavors. again though, what do you want to make? if it's a melomel then clover or wildflower works good because you usually want honey aroma and character but the fruit is the star, are you making something citrusy or tropical melomel then orange blossom is real good in it, or are you making a good tradition honey mead in which case a really great tasting single source varietal will make the best end product, if you have access to different varieties, try as many as you can and see the differences, If you can find a really great raspberry or cranberry or blueberry honey, and want a melomel, match the fruit to the honey or work classic combinations....like a cranberry melomel made with orange blossom honey sounds really good right now.