I'm going to be starting a campaign set in modern day (though I am removing guns, explosives, and cell phones). I'm wondering which system would facilitate deep character building, ability for creative roleplaying, and combat tactics that don't get too bogged down. Any insight?
Can you suggest a movie, book or some other cultural analog you are trying to recreate by "removing guns, explosives, and cell phones?" I'm not sure there are many RPGs set in a modern milieu that would facilitate those exclusions out-of-the-box.
HERO allows you to build complex characters but it's very rules heavy. Very much a risk of getting bogged down in combat. We once had a fight that lasted three sessions. I don't think it's what you're looking for.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.