I just adore 3rd gen Monster Hunter. The music, art direction, and monsters are just peak MH. Portable 3rd is absolutely gorgeous for a psp game and plays wonderfully, especially with tweaks via the excellent ppsspp emulator (seriously, that thing is almost Dolphin-tier). As much as I love Sunbreaks complex, high-speed combat, I do find a lot of comfort in this game's simplicity. It also has the coolest Hunting Horn ever: the Darkest Coffin!
Oh yeah, and this game has the best farm in the whole series. Just the right amount of convenience to avoid feeling like a chore. It just feels like home, and I can say that about the whole game.