Depends on what you want to do with it.
If you want to keep it, its totally your own call. I know some people who would slab every coin they own if they had a chance and then others who break coins out of their slabs because they can't stand them. If its for your own collection its completely up to you.
If you are selling it, it depends on who you are selling it to. If you are selling it online, I'd say slab it for sure because many people are hesitant at spending hundreds of dollars on a raw, non-bullion coin on eBay. And the $30 that it costs to slab it will be made up by the profit you can get from people who bid and know that it is genuine. If you are selling it to another collector or dealer, it depends on who it is. If its a dealer who primarily deals in slabbed coins, I'd say slab it because they might be more willing to pay $$$ because its already slabbed. If its a dealer who rarely touches a slabbed coin, chances are you aren't going to get much more out of him just because its slabbed. If you're selling it to an individual, it just depends on their view of the coin, some like slabbed coins, some are alright with raw coins. Etc.
