You can choose from a plethora of great tools today, all low-cost or free-of-cost.
You said all you are doing is creating web pages and up-loading. For those two chores you can use two specific tools rather than a full-blown IDE:
- File-Transfer app
On Mac OS X, TextWrangler is a famously competent text editor and free-of-cost. Its big brother commercial product adds many more features especially for web site building, BBEdit.
TextMate is another excellent text-editor on Mac OS X. Version 2 has been free-of-cost while in alpha/beta state (seemingly forever). This is my favorite.
Panic Transmit is a superb file-transfer app, handling many protocols including FTP (which you should not be using because of security), SFTP, WebDAV, and more.
The benefits of such tools over an IDE is that they launch faster, run faster, and use much less memory. Being specialized they do well what they do rather than being a jack of all trades.
Specialized Web Tools
Nowadays you can use tools specially designed for building web sites.
The two best such tools that I know of both run on Mac OS X, both low-cost commercial tools:
You can choose from multiple excellent full-blown IDEs that are Java-based so they run well on multiple OSes. You need to install Java before installing these tools. I suggest that after installing Java you then disable support for Java in web browsers because of security concerns.
All have tools for working with web page technologies. In order of preference:
- Oracle NetBeans (free-of-cost, open-source)
- JetBrains IntelliJ IDEA (both in a free-of-cost edition and commercial edition, with most web features in the commercial edition).
- Eclipse IDE (free-of-cost, open-source, originally based on tools donated by IBM)