Im going for 70 to 75 strength, ive got 66 atm. Where should i train? Ive got 70 def and attack and 67ish hitpoints (maybe). Ive been playing pest control lately but im getting bored with it even after taking a break to reach 70 fishing and cooking. Ive also just bought guthans, the healing ability is rather nice :) Any suggestions? :)

Slayer :

 

I simply can't stress enough how much easier Slayer makes combat training. ;)

Cave crawlers. Easy to kill, only 22 hits and easy money to make. Best of unlcoked fairy rings first and use the lost city to bank all drops

Ghostly Warriors are good cash and experience if you've done Haunted Mine and Spirit of Summer. Even better cash and experience if you've also done the Tarn's Lair miniquest. slightly more cash if you've also done Summer's End. They have 44 hp and a max hit of only 5, and since they're undead you can use a salve ammy for a 15-20% boost to your attack and strength. They're a nice choice for training, especially for mid-level players, although I prefer armoured zombies for those with 70 prayer for piety. There's a guide to ghostly warriors in the guides section of the forums.

i say slayer, its kinda slow to train so you need all the exp you can get for it. personally i train every combat skill i can using slayer because depending on you task it can be VERY profitable