Any of the Greek ones are in the named constellation, the letter is the relative magnitude within the constellation. So Delta Serpentis is the fourth-brightest star (as seen from Earth) in the constellation Serpens; Gamma Draconis is the 3rd brightest in Draco; Alpha Centauri is the brightest one in Centaurus, etc.
A lot of these have other names as someone else pointed out: Epsilon Pegasi = Enif; Alpha Cygni = Deneb, etc.
Alphard is Alpha Hydrae.
Mirfak is Alpha Persei (or whatever the genitive of "Perseus" is, I've forgotton all my Latin)
Dubhe is Alpha Ursa Major (won't even try the Latin on this one)
Adhara is Epsilon Canis Major (ditto)
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Ikeya seems to be a comet... did

mess up? Unless you count the one at White Marsh Mall (sorry, that bad joke's been made already)
Ribos apears to be from an old "Doctor Who" episode (this is not a joke).
.... and all references to Laramis that I could find via google.com pointed to FS forums
