My apologies in advance, as this posting may sound like something of a rant.
The first thing I'd like to point out is that I have no real problem with TOAD, Oracle Enterprise Manager, or Windows-based editors. They are all excellent tools that can be extremely helpful in your environment. My objection to these tools is based solely on a lowest-common-denominator argument.
First, a little background. Back in the early 1990's, I was working as a Unix Systems Administrator for a company in Kansas City, MO. Since then, I've worked mainly as a consultant.
Shortly before I started that job in Kansas City, the company had hired a new CIO who let go about half of the legacy (mainframe, COBOL) IT department. The new direction for the company was implementation of Oracle E-Business Suite on Data General Unix (DG/UX).
The mainframe IT staff that survived were being re-trained in the new technology. At one point, several of them came to me insisting that I install ISPF (an editor they were used to on the mainframe) onto the DG/UX boxes because they were struggling to learn to use the vi editor. I informed them that, while they (as a group) may carry enough weight to convince the CIO to direct me to install it (assuming it was even available). However, when they go to their next job and claim that "they know Unix", they would be alone and wouldn't have that leverage. My suggestion was that I would help them to learn the vi editor. (I did offer emacs as an alternative, since it is and was extremely common on Unix systems... Unfortunately, friendlier editors like pico, nano, and joe didn't exist yet.)
If your primary job is software development, a tool like TOAD is generally something you can depend on having. However, as a DBA, you can't necessarily depend on having TOAD (or even Oracle Enterprise Manager) at your disposal at all times. Maybe you're starting a new job and the previous DBA hadn't set up Enterprise Manager (or you haven't gotten around to it yet). Even in environments where those tools are available, they may or may not be working when you need them.
So, my advice? There are certain tools that are almost ALWAYS there. Get comfortable with ssh, SQL*Plus, and vi (or vim). They are your friends.