You are correct in your understanding of digital summing and analog summing. I'll use protools as an example, 'cause thats what I know. There are 2 ways to digitally sum within protools. 1) I can use the 'bounce' function to bounce my multiple tracks down to a stereo pair. 2) I can create a stereo record track, and bus all my sub mixes to it, and rerecord my mix as a stereo pair. I've never A/B the two, but I hear method 2 sounds better. Both of these methods are digital summing. The tracks never leave the digital realm, and are summed within it. Now, if I were to use Protools as simply a multi track playback machine, much like a 2" 24 track machine, or Radar, or ADAT,...and play it back through the multiple inputs of say a Neve console to mix it down, that would be an analog mix down.
Mackie boards tend to not have any color to them, like say a Neve or SoundCraft, or Euphonics. So I don't think you would gain much by analog summing in this set up.
If you are not liking the sound of your mixes, start looking at your mixing techniques. What does not sound right? How did you arrive at that sound. Metal does not have the dynamic range of Jazz. Jazz tends to breath more.

thanks for the reply, very helpful indeed!

well its not so much that i dont like the sound of my mixes...well i guess maybe im looking at it the wrong way.

i get things to sound oh so perfect (at least to me) but then when i sum it to a stereo track and listen on other things its very different sounding much to my dismay.

more and more i am thinking that i did myself a huge disservice to plan to buy studio monitors near the last on my list (i got the mackie board and the delta 1010 first, then an 8 channel headphone preamp, already had the computer of course). ive always been mixing with my ath-m30 audio technica headphones because my computer desktop speakers are COMPLETE crap where as my headphones are at least half decent :P

Glad to help. Your room will affect what you think you are hearing as much as your monitors. Don't go out and buy expensive monitors. Listen to your mixes in a lot of different playback situations, go back to your studio and listen to the difference. make adjustments, and go and listen again. This will help train you to hold a particular sound in your mind. Play back your mix, and stand outside the doorway. What does it sound like? Mono your mix and see what disappears because of phase problems. Fix them. Etc,etc,etc...

the monitors i was looking at buying are:
http://www.americanmusical.com/item--i-MII-BX8A-PAK--m-05_90_394.html

i dont mind spending over 500$ if its going to be worthwhile...and i dont really have much of a choice about the room i am monitoring in :P im 23 running the tech support for absolute poker.com down in costa rica and i am less than half fluent in spanish so i pretty much live where it is convenient and the construction of homes/apt's here are .... well...its shelter :P

Don't buy them without listening to them first. Use a variety of material you are familiar with. Listen to lots of different models. Don't buy based on a review.

ok thanks...i might be slightly limited in my selection, costa rica music shops dont have the variety that i had to choose from back home in WA

however im not sure what exactly im listening for, as i have no reference for what "sound like a flat response" but i will do what i can ;)

That's why I said to bring material you are familiar with. Some cd that you have heard in the car, on earbuds, on the home stereo, and on a boom box and you are very familiar with. Use that as a reference. listen for a hyped high end, are they overly bright? How about the low end, is it natural or are the boosting frequencies to get more punch. Is the midrange too hot and muddying up the sound? Listen at loud and soft levels. Monitors and your ears respond differently at different pressure levels.