"Best" is subjective, of course, but I can tell you some of my favorites:
- Zaya, from Trinidad, is excellent. It used to be made in Guatemala - if you can find a bottle of the Guatemalan stuff, buy it! But, the Trinidadan stuff is also very good...goes for about $45/bottle
- Ron Zacapa 23 Años - was my favorite until I found Zaya. Again, around $45/bottle
- Pyrat - high quality, not as much molasses flavor as Zaya or Ron Zacapa, but a fine sipping rum, $40/bottle
- Mount Gay Extra Old - what rum should be: heavy, aromatic, sweet with a spicy bite on the back of your tongue. Goes great with a full-bodied cigar. $45/bottle
- Ron Matusalem - this one is a bit lighter, for a sipping rum, which makes for a more pronounced alcohol taste on the front, but settles into a nice caramel aftertaste. $35-40/bottle
If you really want sweet, you could try a spiced rum, like Captain Morgan or Admiral Nelson. However, the best of the spiced rum bunch (my opinion) is Sailor Jerry.
Hope this helps get you started!