Do some good "internal" research before committing on a "brew system."
Do you want an all-in-one ("coffee urn" type) system, or a bit more "hands on?"
For 5 gallon all grain batches (hands-on method) you'd need a 10 gallon kettle.
I have an 8 gallon kettle, it's a tad tight to hold the whole pre-boil volume at once, but there's a very easy work-around.
For full volume, no-sparge BIAB you'd probably need a 15 gallon kettle.
Whatever the volume, it needs to be heated, so your heat source needs to be adequate.
Preferences:
To be indoors or outdoors?
Gas or electric?
Using a separate mash/lauter vessel (e.g., converted cooler) or do BIAB?
I prefer brewing indoors and use a 3500W induction plate. I rarely brew outdoors anymore.
Other things needed:
A good wort chiller.
Immersion Chiller (IC) or Counterflow Chiller (CFC)?
Although efficient, I'd avoid a plate chiller; wort needs to be filtered from hop sludge, before it goes through there.
A temp controlled fermentation chamber, such as a fridge.
There are quite a few options and alternatives.
Perhaps kegging instead of bottling?
Kegging (and dispensing from kegs) needs some dedicated equipment itself, count on about $300 at minimum.
