Just taking a minute to post some info for all of the newbies like me out there:
Try out a variety of toons, but if you like melee then pick melee, ranged pick ranged, etc. There are some great heroes with some great toolkits, explore and don;t be afraid to roll random heroes!
Get into a good SG! The MH community is really great and helpful, take advantage and socialize! Go MAVERICKS!!
Jump into MM and XDEF right from level 1. Group up in MM after level 20 and knock your legendary quests out even faster. Again, explore the forums about your hero and you will get great build information and begin to see the strategy you need to acquire items you want for your Lvl 60 heroes.
Some of the G purchases are really cool and quite worth it. Pre sales are great, especially for bonus fortune cards and storage space. Boosts are totally worth it because you speed through your leveling and get a shot at uniques much more often.
Level up your crafters ASAP, donate all your extra loot!! HAVE FUN!!