My personal opinion is that the best would be either Scolopendra morsitans (blue ringleg) or Scolopendra polymorpha (Texas tiger).
That being said, there is really no such thing as a beginner centipede. They're all pretty much mean, nasty and will bite as soon as look at you. The two mentioned are just less prone to it and alot smaller than some of the other species that you will come across.
With the proper respect for them, any of them can pretty much be a starter pede though. Don't ever try to handle them. I would also stay away from subspinipes as they get big and they're one of the nastiest of the bunch.
Not sure about the polymorpha, but I know that I don't see my morsitans much as it's always under it's water dish and rarely comes out.
If you think you're up to the challenge, I might suggest a Texas redhead (Scolopendra heros castaneiceps) While it likes to hide as well, it's out and about much more than any of my other pedes and they get pretty big too.
Just remember 2 things:
1. Never touch them.
2. Make sure whatever they're in is escapeproof.
Well, let's see... there's the centipedes that will try to eat your finger.... there's the centipedes that will try to eat your finger... oh, and there's the centipedes that will try to bite you, chew the wound open, and THEN eat your finger.
That was a tongue-in-cheek way of saying... I'm not sure if there is such a thing as a STARTER centipede when dealing with the Genus Scolopendra. It's more of a "lesser of many evils" kind of situation. You could try keeping a smaller pede such as Lithobia Forficatus, which you might be able to find in your backyard. However, ALL scolopendra centipedes are mean, venomous, and all almost equally likely to take a stab at you given half a chance. The species S.Subspinipes (Vietnamese, Malaysian) seems to be particularly ill-tempered... S. Morsitans or S. Viridis have a smaller mature length and won't be intimidatingly large.
any centipede is a "look but don't touch" pet. so if you understand that and the fact that he will escape or bite you if given the chance, i think you should be alright getting pretty much any species.
i personally would recommend a subspinipes because that's the first 'pede i got. i got my vietnamese because they are relatively cheap and common in the hobby, they get very big and are awesome to watch.
I ordered a Hong Kong Giant (Scolopendra subspinipes ssp.) from Krazy8's last week. It still isn't here yet because of the cold weather, but should be here Thursday. I asked the same question myself before placing my order, but decided that since this was going to be a pet that I would have for quite a while I might as well jump right in and get the biggest, nastiest, most interesting species I could find. IMHO - I think that since all the big ones are at least somewhat dangerous, and since you are going to be extremely careful just like me, you should choose whichever one you like most. I'm also hoping that if I ever do get bitten, pass out from the unbearable pain, fall down the stairs and break my neck, that the species I have chosen will be big enough to eat my entire corpse so that my Wife doesn't have to clean up such a big mess all by herself.