How bad is the XGA screen?

the quality of dell's LCD panels is almost universally loved. The only difference is the resolution.

XGA = 1024x768.

remember: if you don't like it, just send it back and get a new one. If you got a special deal when you bought it and you call dell and ask for the diff screen ususally they'll just make you pay the difference you would have paid.

Currently I run my Sony Trinitron 15" flat screen (not flat panel) monitor in 800x600 resolution.

So what will the difference be like using a 15" notebook XGA screen? Hopefully I'll get used to it.

Of course, I can always buy a monitor and connect to my notebook, correct? I'll probably do that eventually. That way I can sit it at my desk, use a monitor, my favorite keyboard/mouse, and be all set. Then take it on the go when I need to. Think that would work well?

You will actually get used to it very quickly.  I had an Inspiron 8200 with a 15" UltraSharp UXGA screen.  The resolution on that monitor is 1600x1200.  I found it to be excellent and got used to it right away.  I think that you should have opted for at least SXGA+, which runs at 1400x1050.  This allows you to be more productive because it allows you to see more stuff on the screen, simultaneously.  I had an Inspiron 8500 with the 15.4" UltraSharp WUXGA, which runs at 1920x1200.  That's the best screen that I have EVER used on a laptop.  Everything was nice and sharp.  Also, you could see A LOT of stuff at the same time.  If I were you, I would cancel my Inspiron 5100 order and get an 8500.  The 8500 is lighter and has some specials going on right now.  Or if you'd like, you could get the 8600, which has better battery life than an 8500.  Also, you get a FREE DVD BURNER and a FREE MEMORY UPGRADE, with the 8600, all for just $50 more than an 8500.

Hope that this helps.