Having done RAID many times in different ways over the years I'd say that as long as the version of Windows 7 you plan on running supports it, I'd do it. But.. be warned! There may be issues.
For one, I ran into one copy of Comodo firewall that completely blew up the networking stack on XP if dynamic disks (required for Windows software RAID) were present. Also, any BSOD will be followed by a pointless RAID rebuild where it completely copies the contents of one of the drives to the other slowing disk IO for a long time. Also, the entire disks including partitions that aren't RAIDed will need to be configured as dynamic disks which can cause issues accessing them from DOS and Linux. Not usually an issue but it's worth pointing out. One of the things I liked to do was install an OS on each drive that was bootable and have the Stripe/Mirrored partitions accessible from both OSs. If you are going for this type of configuration there is something important in the order with which you create the partitions and convert the disks to dynamic disks. I think you have to convert each disk to dynamic from the OS that boots from that disk in order for it to remain bootable. If OS that boots from disk 1 converts disk 2 the OS on disk 2 will be rendered unbootable (if I remember correctly). If you are going for this type of config, install each OS and have it convert it's disk to dynamic, then create the mirror/stripe partition(s). Other than that, the ability to put the disks in any Windows machine and access the data makes software RAID the clear winner here.
In response to all the posts about how better to safeguard data by backing it up, he's not asking about that. He's asking about which way we'd recommend doing RAID. Your suggestions are off topic. Every time RAID is discussed the same arguments are made. Backups aren't RAID. RAID isn't a backup. Enough already.
I've done software RAID for a long time and I'm a firm believer that it's the right way to do RAID in a lot more cases than it's typically used. Hardware RAID has many proponents and is obviously a profitable industry so there is a lot of money being spent based on it's perceived advantages so I'm in the minority here but that doesn't mean I'm wrong. Expensive RAID array's advantages are getting harder to justify now that Serial ATA has brought dedicated per-drive bandwidth, fast cold (if not hot) swapabililty, and now that multi-core CPUs can handle the load of the software RAID work gracefully. The niche where software RAID makes sense is getting bigger every year. Many people argue that software RAID is too slow, that you need the hardware controller to offload the calculations. I'd like to throw out the fact that I use an 8 drive Linux based software RAID 6 array for my primary storage. Bonnie++ clocks it at 215.2 MB/s on block writes and 263.5 MB/s on block reads. CPU utilization is 45/31% on those respectively but with a quad core machine, using half of one core to do my IO processing when it's writing at that speed is perfectly acceptable. Remember, this is RAID 6 with 2 differently calculated parity chunks, not goofy simple RAID 5 and it's CPU is just a AMD Phenom 9600 Quad with 8 gigs of RAM, not something exotic. I run many virtual machines on top of this array simultaneously and they are nice and snappy. The configuration works quite well and I'd recommend it for a inexpensive, high speed virtual machine server configuration.
For my Windows desktop, I'm currently using my motherboard's Intel Matrix Raid capabilities and have configured half of my drive as a mirror and half as a stripe. The setup has worked seamlessly and I'd recommend it as a reasonable alternative to software RAID. It's slightly cleaner from Windows's point of view and the Intel Matrix controllers are fairly common and, from what I understand, I could put the disks into any machine with Intel matrix raid and access the data in a pinch. I honestly probably would have done software RAID had Vista supported mirroring.