I dont think that there is a better brand than others, stay away from the absolute cheapest ones. But also dont pay a premium for the fastest one you can find either. The little bit of extra speed isn't that important unless you're going to go into the DVD forging business
And you have to buy more expensive blanks to burn faster anyway. The cheapest good quality blanks now are 8x, but up to 16x can be had for not too much more. If you buy a 21x drive or something you'll find that you have to buy much more expensive disks to burn that fast.
You definitely want one capable of DL or dual layer burns. Lets you double the data on the disk for movies or backups that just can't be shrunk down. But since they cost 3 to 4 times more than a single layer disk, it's usually better to split between 2 regular disks.
I have no time for lightscribe. The disks that it can print on are much more expensive than regular disks and it's just not dark enough to be worth it. Someday I will invest in a printer capable of printing directly on disks, but until them buy a box of Sharpies
If you are comfy messing around inside the computer you can save $30 or so by going with an internal and putting it in yourself. If you dont want to bother with that, or it's just not worth the saved money if you have to spend an afternoon messing with it then just get a USB2 external one. They should work just fine and you can more easily take it with you when you upgrade to the next machine.
DVD+R disks are generally thought to be more robust and have better error correction built in than DVD-R disks. The price is generally the same. Initially I'd buy a small pack of both as DVD-R disks tend to be better compatible with older regular DVD players so make sure your DVD player that you will be wanting to play these movies on will play a DVD+R burned disk OK before you buy a huge spindle of them. For archival of data though DVD+R is the way to go. I dont believe there are any drives currently being sold that can't burn to both kinds, so this is just a concern when buying blanks.
I can't advise you on software as I gave up completely on windows years ago now
I do hear Nero bandied about as a good name though. If you buy a decent external drive it will almost certainly come with something to experiment with.