100% VG will give you the most vapor, but you'll more than likely want to compromise with a 60-75% VG/40-25% PG mix. The vapor is great, but you won't feel it in your
throat and lungs as much with 100% VG. Finding the level of nicotine and amount of PG will promote a sensation closer to smoking.
I currently like 65%/35% at 24mg nicotine. I started with 50VG/50PG at 24mg nicotine with the vending options I knew of at that point in time. I haven't tried the current vendor's liquid at different percentages of either. He makes it at that mix, so I haven't bothered to have him mix it differently for me.
Flavor also plays a big role in being satisfied from your vapor.