I'll add just a few notes: You don't need to play the same character type in each game. The character import system allows you to change the class. Infiltrator is the most survivable character in ME1 (IMHO). The sniper rifle can hit targets at ridiculously long range once up upgrade the skills and get better rifels and mods. Adept rocks in ME3. I kinda liked Sentinel or Infiltrator in ME2. ME2 is more a pure action game; the roleplaying comes more from conversation than choices of upgrades. ME3 is radically different -- you can carry and use any weapon, but weight affects your ability to use powers (slows down recharge). But it has more RPG stats elements. However, ME1 kinda went overboard on the stats side. Always take the passive ability that maxes out paragon/renegade. You can get some pretty interesting results (and avoid some pretty hefty combat situations) with high paragon or renegade stats.