First off, let's not start thinking Charmeleon is a BAD card but
still...against Scyther? No way. I won't go over the stuff that's already
been covered but I will drop some of my reasons why I'd include at least one
in every deck imaginable (including Raindance).

1) Free retreat- The single most important aspect to him IMO. Here are the
uses:
A) start with Scyther as your Active Pokemon. This gives you the option of
retreating him cost free if he doesn't match up well with the opposing
Pokemon (like if it happens to be a Fire one). Even if he's facing his
weakness he can't die in a single turn without good coinflips/trainer help.
B) Confusion- Scyther's confused? Try retreating. You lose nothing if you
flip tails and that also gets the "tails" out of the heads/tails equation
(it's a spiritual thing, really). :-)
C) Poisoned- Scyther's poisoned? Retreat him and bring him right back. You'll
only catch the initial 10 points (or 20 from Nidoking) but now you're back to
where you started. Add a Potion and you've lost nothing.
Status Effect- Attacks like Leer and Tail Wag, for example, affect the
defending pokemon only (meaning that particular Scyther while he's in). Look
at this scenario...Eevee does Tail Wag = Scyther can't attack, Scyther
retreats = Tail Wag is removed from play, Scyther returns = free from all
effects, Scyther smacks the beejeebees out of Eevee. Leer really isn't a
problem as it's only used by Fighting Pokemon (I believe) and worse yet, by
Fighting Pokemon with Weakness to Grass. Scyther would LOVE to see Rhyhorn
use Leer. It makes me giddy just thinking about it.

2) Resistance to Fighting- Hitmonchan becomes weaker than Magikarp against
Scyther. Hitmonlee gets one attack to a benched Pokemon before dying. Even
Onix is turned into a mortal. Haymakers all over the world turn to Electabuzz
(and pray for good coinflips).

3) Setup- It's not that hard to get a starting hand of Scyther, Grass, DCE. I
use Two Scythers, two Grass energies, and two Energy Search (which was a
horrible idea before I actually TRIED it) in my Psychic deck and have never
looked back. If it is your goal (maybe ignoring another Pokemon) then you can
easily get Scyther up and running by turn 2. Also, starting with Scyther,
playing a Grass on him, then doing Swords Dance forces your opponent to
change their whole opening Strategy. if you win the coin flip and go first
then the defending pokemon is as good as dead barring a Big Pimp Colorless
(Chancey, Kangaskhan, Lickitung).

4) HP- 70 point basic. Needs no explanation.

5) Splashability- This may be reason number two for him. Scyther and a Grass
goes into any deck that can be constructed immediately and cheaply turning a
mono color to a double color. Most smart decks only use about 12-14 Pokemon
cards anyway. You put in 3 Scythers and that's like replacing one line of a
regular deck. In a slightly related note, Team Rocket Squirtle may become a
new Splash weapon as Water has never had one.

Scyther Killer Combos- Scyther/Fossil Haunter, Scyther/Dark Kadabra, 
Scyther/Ponyta.

Charmeleon, on the other hand, is a good card but has absolutely no
advantages other than those that come from being a Fire Pokemon. This also
includes all of the weaknesses of being a Fire pokemon also (energy discard,
Water Weakness), unfortunately. Being a Stage 1 isn't much of a disadvantage
as you can have both Scyther or Charmeleon powered up on turn two with
Charmander having done some damage on turn one.

Now who's dissing Base Set Gastly? Just kidding!!!

Later...

harerazer@aol.com