I'm a designer using Snow Leopard on a MacBook Pro 15" (i7) with 8GB Ram, 500GB (180GB free) (2010 model).
I usually use Chrome (4/5 tabs), Firefox (1/2 tabs), Skype, VM Ware Fusion (with Win XP, using only 512MB), Photoshop CS5, Adium, iTunes, maybe Filezilla.
Photoshop is the main Ram user. It can eat up to 3GB or more as time rolls by, and I'm not working with very big files, 50mb max, and only 2 or 3 open.
When I start opening programs everything works fine. It's later on that you see that you have very (and I mean veryy) little Free Ram left. Between 8MB and 15MB. At the same time I have 2.21 GB of Inactive Memory.
The machine gets much slower once you get below 150MB of Free Memory, and it's a total lie that Inactive Memory gets released onto other programs to overcome this slowness. It never gets released until you close the program.
I wanted to post a screenshot of my Activity Monitor but your site doesn't allow it if I'm a new user.
Once your Free memory gets to these levels (15MB), the Page Outs start increasing and the Inactive Memory never gets released. It gets laggy.
Please don't tell me that a 2010 Macbook Pro with 8GB is not enough to work with Photoshop on small to medium sized files. Normal users (internet, skype, movie watching, etc.) won't have this problem, but if used for design or more heavy tasks (which I believe is this machine's main purpose), it doesn't work properly.
I think this is a very important issue that has never been addressed. I don't know if Mountain Lion has solved this, but I've searched around and haven't read good comments (they even say it eats up more Ram).
Do you know if a MacBook Air i5/i7 8GB 256GB SSD will improve on this matter? Do SSD's improve Ram usage? I'm planning on changing the MacBook Pro (not because of this, because of it's size).