Which of the Ultima is the best for start?

There is a version of U4 that has improved graphics, everything else is the same though.

Ultima 4!!!

then Underground

then 7….

then ultima online…

you could probably skip the rest

UIV running in DOSBox.

I don't know about UVI needing a lot of hardware… I ran it when it came out on a old 80386 (granted, I ran DOOM and Might and Magic III on that poor thing) with only the base 640k of RAM. UVI ran fine, thoguh I ran around and stole everything in the game, creating my own little fortresses in every town. I'd planned on moving everything to Lord British's Castle, but never did.

UVI has remained on my computer from that 386 until the last one. It's only not on this one because I'm still trying to make Windows actually work for a change. When I'm pissed off enough to dig out a Linux disc and install that along with DOSBox, it'll join all my other old games with DOSBox and I'll probably spend more time with them than I do my PS2 and other newer games, as usual.

Speaking of Ultima VII, I tried it for the first time not long ago with Exult. I was pretty impressed with the storytelling and general atmosphere of the game and I plan on going back and playing through it someday soon.

I have one question though, the combat seemed somewhat confusing and chaotic to me, do you have any control at all what your party does in combat or is it completely automated?

it's pretty automated. IIRC you can set what type of combat they do (ie beserk, defend, etc.), but I could be wrong. I know that U6 you could, but can't remember for U7.

Yeah, the combat is pretty crazy. You can only control The Avatar and you'll definitely need to make use of the target button. To make sure I get some exp, for the purpose of staying alive, I usually kick everybody out of the party and kill things on my own for a while.