It really doesn't matter. You will probably find a little more horespower in
the 2.0 Framework. One thing though- if you have to ask this question, I
suspect you've got an awful lot of work ahead. Best of luck, and remember:
"Don't reinvent the wheel".
Your question is too vague. Is this gonna be for a single site, or to crawl
the web like Google? Becuause if you are looking to implement a site search
then try Searcharoo. Otherwise, you have a monstrous task ahead of you, and
your choice of Framework version is the least of your worries at this point.
Hope this helps!