1. You may want to spend a few $ to get a copy of
Cycling About's buying guide.
2. As is the case for essentially any sport, or any activity for that matter:
- do not buy "cheap" (say, $400). You'll regret.
- do not buy top-of-the-line. You'll regret.
- you'll know more about what you want once you're no longer a beginner.
3. If you can, invest time (and maybe money) to research "contact points": the saddle, the handlebars/grips, the pedals,
4. wrt racks, as mentioned above, failure would be surprising. Loosing a fastener is much more likely -- use loctite blue (part can be removed) and carry spare fasteners.