How can I dual boot Ubuntu and Win 7, with shared data

When installing Ubuntu, it should detect your existing Windows installation, offer to resize the partition (although on the next boot of Windows, it will likely complain and force a chkdisk, hence it may make sense to make the spare room for Ubuntu from Windows itself) and, additionally, should configure the bootloader (GRUB2) to contain boot entries for both Linux and Windows.

In terms of sharing media between the OSs, if you don't have any media files that are larger than 4GiB (a limitation of the FAT32 filesystem), I would suggest creating a "bridge" FAT32 partition that is read/write accessible from both OSs. If you're fairly certain that you only will be reading from Linux, you can leave the media where it resides on the Windows install since Linux can read (and, to some extent, write, but not without some issues) NTFS.

Now, the two-disks-as-one may throw a wrench into things. Were you planning on setting them up as a RAID0, RAID1, or JBOD? And through what mechanism were you going to configure the collection of disks? I ask since using the so-called "raid" controllers on modern motherboards can sometimes be used by both operating systems (on Windows you need to install whatever came with the laptop, in Linux you would need to check to see if the chipset is supported by something like DMRAID), but there's no guarantee and, additionally, in my own experience the onboard "raid controllers" tend to be fairly unreliable (can't tell you how many times my workstation at work had it's RAID0 array on a ICH8 affair fail without either disk failing, after which I requested mine be converted to a RAID1, which still has had hiccups, and that the default for new workstations not be setup as RAID0 on these machines). If you really want to push forward, it should be doable but will take some effort and may cause headaches, just a fair warning (these days I only trust actual HW RAID cards or in-OS SW RAID)