Super Mario Galaxy won't start slower than Halo. It will have an immediate attach rate of at least 25 %, maybe 30 % or 35 %. That happened with all Super Mario titles down to New Super Mario Bros on the DS.
Super Mario 64 and Super Mario Sunshine started slow because there was no big installed base, but there will be 16-19 million Wii owners by the end of the year, so I'm pegging Galaxy at 4 million minimum for this year with potential up to 6.5 million. With that it has a good chance to outsell Halo 3. Super Smash Bros Brawl won't be out in Europe this year and therefore has no chance to come out on top.
And surprisingly, a lot still depends on the quality of each of these games.
Hardcore gaming is a bubble economy blown up by Microsoft's $7 $6 billion losses.
