Well, me of course. It really depends on what you like about sherry though. Here are some ideas...
The very sweet sherries such as the Creams (Harvey's Bristol would be an example) will not be very useful as a cooking ingredient, so if you're not going to drink it much, I wouldn't bother with them. Unless your plan is to use the sherry exclusively for desserts. Then this is what you do want. You could, I think, get a Harvey's Bristol Milk, which is less sweet but could still be used in desserts and might be more useful otherwise.
What I like about cooking with sherries is that there presence is noticed without its being overpowering. Generally.
Typically, you would use a dry sherry for cooking. Some are so dry that your mouth would go into shock. Tio Pepe, for example is very dry and probably too dry for cooking. It would be a 0.
So mid-range dry might be....and Amontillado, which is probably a 1 on the sugar scale that starts at 0. It's generally inexpensive and just fine for sipping, even if you like ice with it. An Olorosso Dry would be okay too. It is probably classified as an MD.
There are a whole lot of absolutely divine sweet sipping sherries from small bottlers in Spain. These are so wonderful that you just wouldn't think of using them IN food.
I dunno. It really depends on what you want to do with them. They run the gammut from $10 to $1500 a bottle and the whole range of sweetness.