rsa-e / rsa-s distinction in --version output

[MindFuq]

Doing a gpg --version gives:

gpg (GnuPG) 1.2.0
[...] 
Home: ~/.gnupg
Supported algorithms:
Pubkey: RSA, RSA-E, RSA-S, ELG-E, DSA, ELG
Cipher: IDEA, 3DES, CAST5, BLOWFISH, AES, AES192, AES256, TWOFISH
Hash: MD5, SHA1, RIPEMD160
Compress: Uncompressed, ZIP, ZLIB

It's strange that RSA, RSA-E, and RSA-S are all listed.  I can see
just listing RSA for simplicity, or just listing RSA-E/S, but all
three?  Why?  It's confusing.  If RSA-E is for encryption, and RSA-S
is for signatures, what is meant by RSA?

It seems like there shouldn't be any distinction at all.  If I
generate an RSA key, technically that key can be used for encrypting
or signing.. In fact, signing is encrypting; correct?  Signing is just
taking a hash and encrypting it like it's a message, only the in this
case the private key is used.  The algorithm doesn't care whether it's
a -E or -S key.

Equally confusing, ELG and ELG-E are listed.  No ELG-S?  With the
expert setting, I can create an ELG key that can be used to sign.