I smoke about a pack to a pack and half a day. I'm pretty open as far as a budget is concerned. I don't mind spending a little extra money for a quality product. I'm really worried about battery life and how many puffs the ecig would give me. I really don't want an ecig that I will have to charge/refill 3-4 times a day or more.
To get what you desire you will need to disregard the cigarette look-alike batteries. They only last 3-4 hours at best and you will soon tire of changing batteries and recharging them.
General rule: The bigger the battery, the better the vape and longer the battery will last. Battery life is figured in mahs. 100 mahs is = to 1 hour battery life in use.
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The mid-sized eGo batteries are about the size of a long skinny cigar. The largest battery available for them is generally a 1000 mah that will give you 10 hours battery life. Consider all the eGo type batteries to be ultimately disposable as they are not as durable as a mod, and are rated for 250 charges. Then performance will decline and you will need to buy an entire eGo to replace it.
Mods are simply battery holders for smaller replaceable batteries. They are made of thicker aluminum or steel tubes and will last years. The batteries that they use are cheaper (<$10 each), between the size of a AA or D size battery, so that you can easily carry a couple extra's in a plastic battery case, and will last anywhere between 9-24hr depending on the battery size, with an overall lifetime of a year.

size comparison of cigarette, mini-ecigarettes, and eGo type batteries.

example of a small tube mod: Altsmoke BB uses a 14500 battery that will last at least 10 hours.

example of a larger tube mod: Altsmoke Silver Bullet uses an 18650 battery that will last all day. On top of the Silver Bullet is a cartomizer tank in which juice is stored. Inside it is a cartomizer which heats the juice to make vapor. These tanks can hold a total capacity of 3-7ml of juice, more than a day's supply.
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For a simple breakdown of heating elements to attach to your battery or mod, follow this link.
http://www.e-cigarette-forum.com/forum/blogs/baditude/3230-proper-terminology-carto-tank-what-lol.html