ssamra26:
Yes, it's better if you don't have subdomains. Now, buying 1k .com will be expensive, to say the least; so I would buy a bunch of .info domains which are 1-3$ depending where you get them and scale up.
Spin your content, you don't want the exact same thing; change themes, if you choose to use adsense, I would use one account per autoblog(but then again, my blackhat works on a paranoia based logic), don't use analytics.
Use one C class ip per autoblog.
An alternative to the one blog per domain, would be, have something like a main domain(say, my-viagra.com) and several "sub-blogs" in subdomains, linked from the main blog to help a little(free.my-viagra.com, etc); this way you get several blogs per domain, and use a single IP for them all; of course, they could get banned, but who cares, it's just a few blogs.