If you just want to look at a file, there's a great free tool to do it: UniversalViewer.
It can open a 1GB file as fast as a 1kb file (because it only pulls in what it needs to show the screen full of text you're looking at.) And there are times when you may well need to look at some very large files, especially when troubleshooting CF servers, like I do.
And actually, as its name implies, UniversalViwer can view far more than just text files, including images and more.
I've just only ever used it for looking at log files, for which it excels (and yes, you can search within the file, set it to tail files, and more.)
I've been touting the tool for years in classes and presentations, and I was about to mention it in another blog entry, but then I realized I'd not blogged about it on its own. Rather than have the reference lost in another blog entry, here's its moment to shine!
And yes, I do realize there are several other tools that can do this. I list this one and several others in a category of my CF411 list: Generic File View/Log Analysis Tools. (Note that there are some nifty tools in that category there for looking specifically at CSV files, as well as other entire categories for specific kinds of logs, like CF logs, web server logs, windows event logs, etc.)