I always keep my starter, and mostly pick the fire starter (with an exception for oshawott that thing was just too cute). When playing omega ruby most of the time I was just in awe of how epic it was and how good it looked. I especially enjoyed the DexNav functionality which really helped with my start goal: completing each area before heading to the next (in terms of dex and items). Though after a while I gave up on that because it took too long and I really wanted to play on.
As for the level of my pokémon my starter is overleveled as I always keep it up front. Blaziken just owns straight through everything in ORAS. The rest of my team is composed of pokemon I encounter, like Mightyena - I actually leveled that to 71.
For me gen 3 and its remakes are the best pokemon games I've ever played, mainly because ruby was my first ever pokémon game on a real gameboy.
I started playing X lately (got a second hand copy), started of slowly, exploring everything, but as I ventured onwards I got really over powered.... My delphox was 80 when I first reached the E4..... I still enjoyed the game but I just blazed through it and catching pokémon was undoable with my delphox up front as I would just one shot almost everything. My plans are to back track the whole game, picking up what I've left behind, battling the last batch of trainers, getting my style maxed so I can get fancy clothes, learning all the skate tricks to enter the lost hotel, and lastly catching mewtwo and zygarde. (all while using Sceptile with false swipe to catch everything ^^)
I think I'm one of the few persons here that has NOT completed his pokédex.... I'm still slowly working on it
I'm around 600 pokémon on OR, and after "completing" X, that will be a bit more
My final goal is to have all 719 pokemon from 1-719 in my boxes
Then, and only then will I be satisfied :D
Thanks for reading ^^