You can start with the stove-top (aka BIAB) all grain method to get a few batches over your belt before you decide to invest in more gear. I would opt for at least a 32 quart pot/kettle though. You can go lower cost and get a solid aluminum pot, and convert it into a kettle yourself (install the ball valve)... I did this with the valve assembly (no-weld type) from my LHBS... Was rather easy to do too. I went with the 1/2" valve, so that it would drain faster.
If you have a cooler that's 40qt, or larger, then you have something you can convert into a mash tun.
If your stove can get ~7 gallons up to a boil (and maintain it) at a decent rate, then you don't need to get the propane burner... I will say, having one (a propane burner) is really nice though.
If you do opt for the BIAB method, then you'll need at least one, or two, good sized pots. You'll want a pair of (at least) 24-28qt pots to use. If you decide to do the no sparge method, then you'll need an even larger pot...
For ME, I could only brew moderate OG batches (under 1.075 OG) due to pot and stove limitations. With the mash tun (converted cooler) I can make pretty much anything I want, either 5 or 10 gallon batches, with ease. The stove in my kitchen had a very difficult time getting even ~6 gallons of wort up to a boil. Then it could barely maintain it. The propane burner doesn't even blink at 7 gallons in my 32qt kettle... It makes short work of 12+ gallons in my 60qt kettle too.
So a lot really depends on what you want to brew, how much you want to spend, and what method you want to employ. Just remember, you're not locked into one method, you can easily switch it up depending on what you're brewing.