"You just have to ask for his or its help at the time of death, according to the Tibetian Book of the Dead."
Wow. Tibetian Book of the Dead. Ok.
"Besides the Christians are so few in number, they could not possibly populate heaven."
Umm....How are you getting this? There are a lot of Christians. And since when was heaven a place that had a minimum population?
"Then again in John's Revelations it says that only 144,000 make it to the presence of god."
No it doesn't. Read Revalation 7:4-10
7:4 I heard the number of those who were sealed, one hundred forty-four thousand, sealed out of every tribe of the children of Israel:
7:5 Of the tribe of Judah were sealed twelve thousand,
Of the tribe of Reuben twelve thousand,
Of the tribe of Gad twelve thousand,
7:6 Of the tribe of Asher twelve thousand,
Of the tribe of Naphtali twelve thousand,
Of the tribe of Manasseh twelve thousand,
7:7 Of the tribe of Simeon twelve thousand,
Of the tribe of Levi twelve thousand,
Of the tribe of Issachar twelve thousand,
7:8 Of the tribe of Zebulun twelve thousand,
Of the tribe of Joseph twelve thousand,
Of the tribe of Benjamin were sealed twelve thousand.
7:9 After these things I looked, and behold, a great multitude, which no man could number, out of every nation and of all tribes, peoples, and languages, standing before the throne and before the Lamb, dressed in white robes, with palm branches in their hands. 7:10 They cried with a loud voice, saying, "Salvation be to our God, who sits on the throne, and to the Lamb!"
John mentions that there are 144,000 people 'sealed' from each of the twelve tribes of Israel. 12,000 from each tribe.
But then in 7:9 John mentions a "...great multitude, which no man could number, out of every nation and of all tribes, peoples, and languages..." He say these people right after he saw the 144,000. So they were both in the presence of God. Sorry, your wrong.
"God wants all of us and gives all of us the chance for salvation in lifetime after lifetime..."
Nope. This is the only life you got. I'd use it wisely. :)
"But personally, I think that salvation just means that you qualify for a job (with duties, responsibilities, etc) in heaven. We on earth are just audtitioning for the next gig."
Interesting thought. On a related note, there is a common misconception that when you die, you become an angel (I'm not saying this is what you said, but it is simmilar). This is not true, because angels were created seperate beings from us and God. The devil, Lucifer, was the highest ranking angel, but turned evil, and God threw him out of heaven.