If long-term your plan is that company is just going to be _you_ then keeping it simple is the right idea. Using a simple workflow with a Google form feeding into a spreadsheet with status on it will work perfectly well.
If you think that you're going to be dealing with the same customer on multiple occasions so you'll want to record the history of your interactions then you'll need a CRM. If you want to build up a database of people who showed interest that you'll then talk to regularly, then you'll probably want CRM. Finally, if your intention is to scale the company and so have many people talking to prospects and customers then you definitely need CRM.
Salesforce is the most well-known and it's relatively easy to get started with, very Cloudy and has a platform so you can build operations on it. You reference Oracle, they (and Microsoft) have complete enterprise solutions which are at a different level. SF is more at the middle of the pack. It's well-known and many people are familiar with it. But you're right, it's a full CRM so it does far more than just tracking your leads.
There are other light-weight Cloud solutions out there, and SugarCRM is probably a good Open Source option that (as a technologist) you could easily use.
