Ammo will be the cause of 99% of your problems with semi 22's.
Bulk pack ammo, while nice and cheap, is sometimes just that. Cheap. You will get batches of under-powered 22 rounds in the bulk packs. That is the trade-off with the rounds costing a bit more money (Remington 525 pack vs CCI 50 pack).
Swab the barrel every 100-200 rounds and clean it well at the end of the day. Most, if not all, of the guns mentioned in this thread will perform well for you.
Personally, I like Burley's suggestion. Gives you more options for when you want to shoot with the big boys.