Two alternatives that noone else has mentioned yet:

# both branches are very long

sub wibble {
    return 1;
}

sub wobble {
    return 2;
}

sub sg {
    return COND ? wibble( @_ ) : wobble( @_ );
}
[download]

# one branch (symbolised here by `return 2`) is much shorter than the 
+other

sub wibble {
    return 1;
}

sub sg {
    return wibble( @_ ) if COND;
    return 2;
}
[download]

If you avoid monolithic conditional code blocks, most of the time your question will trivially resolve itself.

Makeshifts last the longest.