You'll be able to complete the National Dex with those games, but Event Pokemon aren't available (they are optional to complete the National Dex though). The following Pokemon are unavailable in the games without the help of special events or spin-off games:
Mew (will likely be available in Pokemon Ranch on Wiiware)
Lugia (can be traded to GBA from Pokemon XD on Gamecube)
Ho-oh (can be traded to GBA from Pokemon Colosseum on Gamecube)
Celebi
Jirachi (can be transferred to Ruby or Sapphire from Pokemon Channel on Gamecube)
Deoxys
Phione (needs to be bred from Manaphy)
Manaphy (can be transferred to DS from Pokemon Ranger)
Darkrai (may be available from hotspots when the next Pokemon DVD is released in Australia)
Shaymin
Arceus
Also, you'll probably need to play the GBA games multiple times for Kanto and Hoenn starters, as well as other Pokemon such as the Johto starters (one of the three can be chosen in Emerald, or all three can be caught in either Colosseum or XD) and the Johto dogs (in Firered and Leafgreen the one that has a type advantage against your starter will appear, or all three can be caught in Colosseum).
Happy catching!
02/06/2008
Pokemon Diamond
Sydney, NSW