Regardless of whether you choose to participate, I'm ranking my favorite 15 here.

1st Place: Norris
Pretty much just because I think he's got the best outfit in the entire game. Hell, it's the best of the Chrono series. It may just be military with a nice jacket, but it's posh. I'm also a fan of gunslingers and like his Techs. He's even got nice hair.
2nd Place: Lynx
I wish there were an option to keep Lynx's form or at least his clothes. I've always thought Serge's outfit was lame. Lynx is cool. Not only does he have a superior outfit, but he's a bipedal cat. Finding out who he really is makes me cringe at whacky plot twists appearing to have been thrown in "just for the hell of it," but regardless of whether I still get to use his Black Innate Techs (sometimes I wished I could've been using his scythe), he's still choice #1 for main character.
3rd Place: Harle
She's just so cute. I love her accent. She's a much more endearing version of Harley Quinn.
4th Place: Dario/Glenn.
Well, actually, I haven't played as Glenn yet or really experienced much of him in the game. But he's Dario's brother and Dario's awesome despite the fact that you only encounter him as an optional fight that's a bit tricky. I don't prefer to be stuck with the Masamune and, in fact, I think the Mastermune is a stupid name (I love the design though), but again, Dario has a plush outfit and impressive skills. Back to Glenn, I hear he not only gets to use the Einlanzer but dual-wields them. Tops!
5th Place: Turnip
His speech pattern is totally Frog. Like Harle, he's just so cute. A tiny little VegeKnight (minus the "shining armor").
6th Place: Grobyc
I like machines. I like robots. I like automatons. I like synthetic humans. I like people with artificial parts (they're interesting). I like cyborgs. Really... I've said too much already.
7th Place: Skelly
Pretty damned impressive meeting a dead guy with an intact sense of humor. He may not have the greatest outfit or the greatest skills, but Skelly is one of the more entertaining characters in the game. Funguy is the other but I'll only be including the one entertainer in this list.
8th Place: Karsh
I actually kind of hate his name. But once he's recruitable, I like his attitude. He's pretty enthusiastic, yo!
9th Place: Nikki
I'm usually not the biggest fan of Japanese pop artist who tend to dress up like chicks to score more fans. But Nikki is still a fun character and Chrono Cross is the game that got me used to this J-pop stereotype so I could better embrace Genesis/Gackt when Crisis Core was released.
10th Place: Radius
Good name, ol' man. Pretty impressive skill for a cane-walker. I'm never really been a big fan of the aged guru archetype, but in most shows you don't see much of them. Being able to play as Radius gives you more of a chance to appreciate what the geezers are really capable of.
11th Place: Guile
I've only recruited him once and then I didn't complete the storyline before resetting the game to choose another path. My deal was that I felt his storyline didn't offer me enough material gain. Aside from that, I thought Guile neat. Like (I presume) Pierre or Nikki, he's one of the first characters you can recruit who actually starts off with his level 3 Tech available and it's teleporting a rod into an opponent's sternum! He and Razzly are the only two characters in the game that float rather than walk (well, he WALKS but floats rather than running). Like Lynx, I think his outfit is dignified also.
12th Place: Kid
Gotta love her. Well, maybe love is a strong word. Look how far down the list I've put her. Still, she's the first character you recruit who can eventually steal from monsters and she's not bad to look at. I bloody hate that accent though, mate!
13th Place: Steena
She's mostly on this list because I like her level 7 Tech.
14th Place: Pierre
Basically just because I think it's awesome when the Prop Sword transforms into a Hero Blade.
15th Place: Pip
Whatever the hell this thing is, it's "evowving." I never used it in battle all that much so the first time I saw him evolve was when I was battling Time Devourer and repeatedly running away when the Chrono Cross wouldn't work. Imagine my surprise when Pip suddenly sprouted wings and turned pink. At first, I thought he was gonna simulcast and ruin my sequence which would have pissed me off (which I eventually was anyway because the Chrono Cross isn't working).

Well, that's my list. I might've put Greco in there somewhere but like with Skelly, I decided to include just one masked guy.