Lion SSD and HDD symbolic links - user folder?
There is a Library folder but it is hidden on Lion by default when using Finder. You can see it in the terminal :

Macmini:tyr root# ls -ld Library
drwx------@ 36 tyr  staff  1224 Apr 10 01:42 Library


FWIW I have a SSD + HDD setup myself and I've left my homedir on the SSD so I will still be able to login if the HDD ever fails, but I've linked all dirs containing large file to the HDD :

Macmini:tyr root# ls -l
total 1552
drwxr-xr-x  17 tyr   admin     578 Mar 10 23:02 Applications
drwx------+  5 tyr   staff     170 Apr 13 02:15 Desktop
lrwxr-xr-x   1 root  staff      35 Dec 31 08:15 Documents -&gt; /Volumes/MiniHD/Users/tyr/Documents
lrwxr-xr-x   1 root  staff      35 Dec 31 08:19 Downloads -&gt; /Volumes/MiniHD/Users/tyr/Downloads
lrwxr-xr-x   1 root  staff      33 Mar 18 16:11 Dropbox -&gt; /Volumes/MiniHD/Users/tyr/Dropbox
drwx------@ 55 tyr   staff    1870 Mar 16 23:06 Library
lrwxr-xr-x   1 root  staff      32 Dec 31 08:19 Movies -&gt; /Volumes/MiniHD/Users/tyr/Movies
drwx------+  6 tyr   staff     204 Feb 19 04:35 Music
drwx------+ 24 tyr   staff     816 Apr  4 08:09 Pictures
drwxr-xr-x+ 88 tyr   staff    2992 Apr  8 11:17 Public
drwxr-xr-x+  3 tyr   staff     102 Dec 31 08:02 Sites
lrwxr-xr-x   1 root  staff      41 Dec 31 08:30 VirtualMachines -&gt; /Volumes/MiniHD/Users/tyr/VirtualMachines


You'll notice Music isn't a link, that's because I've changed that setting in iTunes, so there's no need to replace it with a symbolic link.

Edit: creating symbolic links

(As always having a backup is essential.)

To create these kinds of symbolic links I recommend logging in as a second user then using root in the terminal. E.g. you want to create links for User1, then login as User2 and in the Terminal do :

$ sudo su -
Password:
Macmini:~ root# cd /Users/User1
Macmini:User1 root# mv Documents /Volumes/MyHDD/
Macmini:User1 root# ln -s /Volumes/MyHDD/Documents Documents


The above commands moved the "Documents" folder in the "User1" homedir to an external volume called "MyHDD", then created a link called "Documents" to the place where we moved it.