The WebmasterWorld Forum has led an interesting discussion on the topic "How does Google determine which pages to Crawl?" Obviously, Google has recently introduced a different parameter for crawl priorities. Otherwise, it used to index the pages without crawling.
The vital factor that affects page crawling and indexing is the Page Rank (PR). Usually, Google priorities the page, which has good PR, than pages having lower Page Rank. Therefore, it is very important to decide how to place the links in the home page.