I am looking into installing 2 sub panels. The reason for this is the location of the current box in a finished room, with a finished ceiling. And the rest of the basement is NOT finished, and I don't want to mess with running a bunch of stuff through a finished ceiling. So I figured I would run a sub to a different part of the basement for it's needs, and then I want to run another one to my garage to make a shop. So the questions:

1 - Basement 2,500 square feet
Probably no more than a 60ft run, once I decide where I
Am going to put it. There will be general lighting, fitness room with a treadmill, TV,
Fridge, computer, guitar equipment, etc. Nothing too fancy.
Would 50 amp be sufficient?
What gauge wire would I need? #6 in 1" conduit?

2 - Garage Shop
Again, no more than a 60ft run.
Going to have an 80g air compressor, table saw, lighting, etc. Room A/C / Heater.
Nothing really used all at the same time. Mainly for airbrushing. Some ventilation
fans for fumes.
Should I run a 100 amp out here?
Again, what gauge wire, and what conduit?

3 - My main breaker is a 200amp that these would feed off of. THere are only 2 slots
available. 3 more will be opened up for current basement stuff that would be moved to
the new subpanel. So this would give be 5 openings. There are many things that
could be put into the single slot / 2 breaker type, opening more. Is this just
dangerous? There is no way all of these things will be used at once to even come
close to using the 200amp

4 - There is a good location outside for a jacuzzi. I would like to run the wiring "Just In
Case" the wife lets me get one. And I would want to do it now, because once the
Ceiling and basement is finished, I won't be able to run it. It's a walkout basement,
And a drop ceiling just doesn't look right. This I would want run from the main
Breaker, or my basement sub breaker?

Expert advice would be appreciated! Thanks if anyone can help!

#6's for 60 amp may work better, #10 for ground. Hot Tub may take 50 Amps, #6's.
3/4' PVC plenty for 6's, 1" not bad for upgrade later, maybe larger, small price difference . The trench is the problem(money).
#4 for 100 amps.
2-#6, 1-#8, 1-#10 for ground. For Jacuzzi. Plus 50 Amp GFI

Everything is actually being run within the basement using regular conduit. Do I still need to run a ground wire, or do the connections of conduit act as the ground?

No trenches necessary, the hot tub would go on a patio that is directly by the house. So all would run interior, directly to the outside of that wall. Then the water tight flex stuff from there.

So to sum it up...

Garage - 100 Amp breaker I should use #4, all around I assume.
Basement - 60 Amp breaker #6 all around and #10 for ground
Hot Tub - 50 Amp breaker #6 all around just to be safe and #10 ground

Grounds are necessary even when using conduit to run everything I assume? So I will have 4 wires running to all subs.

I would pull separate ground. With conduit, if it became disconnected, and short existed,
It would not trip breaker, That section of conduit would become live. Dangerous.
Often you can reduce neutral 1 size, If all three the same, no question.
Keep the grounds and neutrals separate, do not bond neutral to ground.

Yes, a ground wire. I see a lot of pulled apart conduit hanging by the wires. Rust and paint are a problem too.