While I'm comfortable in the command line, I find a GUI easier to navigate and able to fit/scroll more information at a time.
In the Windows world I'm used to TotalCommander, which has a really nice integrated viewer that works with arbitrarily large file sizes. It doesn't do "less", but presssing F2 is easy.
I don't know what the equivalent SL/RedHat (Gnome) program would be. I mostly use gEdit but it's a dog on large files. Something that opens 1GB files really fast, is able to search forwards and backwards and select large amounts of text.