A good 975 skin?

There are no "bad" champions in a cyclical meta, some come into extreme power and others drop out of it with even the most slight nerfs and buffs. See Khazix. See Syndra. See Fizz.

Pick a champion you're comfortable on and "love" to play, buy your favorite skin for them.

Just watch the skin sales.

For one, there really aren't any "bad" champions. Sure there are going to be times in which X champion is better then Y champion ( vs as an example)

Just because Braum is more versatile, doesn't mean Taric is bad. That point and click stun + armor aura makes assassins cry (minus Zed, cause **** Zed)

But for skins, just find a champion you really like and get the skin you personally like best. Skins should be used to say "I like this champion enough to put money into them"

I like WW new skin more than Hyena.

Edit: Oh hey....Hyena Warwick is going on sale. http://na.leagueoflegends.com/en/news/store/sales/champion-and-skin-sale-0220-0223