Too bad. Would have been a great time to get a server. Anyway, you can never have too many backups, and I think you have done a great job covering all your bases. I may offer a few tips. And, you may want to streamline a little.
The first thing I would suggest is two hard drives. You can use two partitions, but if you lose the drive you are completely dependent on the backups. You also didn't mention anything about RAID. You could either go with a 80 to 120 GB SSD drive or purchase two and have a mirror. If you went with the mirror, you could partition that and have a system and data drive. You could add a 1 TB drive for backups. Or you could have an SSD for the OS and a HDD for your data.
I used to use SyncToy a lot, but I don't think it is robust enough to depend on. I remember you could use quite a few options such as copy, sync, left to right, etc. I always worry about syncing if something gets set up right to left rather than left to right and data is deleted from the backup and then overwrites the real data.
I do applaud your complete image backup, which most don't do. It is the most important part of the backup process. You can then backup to multiple drives with multiple full backups or use incremental. The NAS is a great selection, and it can be RAID as well. One thing I have found, though, is some backup programs back up great to NAS, but for whatever reason the backup can be hard to browse to. I have no idea why.
It's interesting, because Acronis used to be my favorite software, especially when it was Acronis True Image. It was easy and bulletproof. Then, they started making it more and more difficult with vaults and stuff, I couldn't figure it out. Plus, its VSS writers can demolish native Microsoft VSS writers. I do have an inexpensive one on my computer, which is the home version, and it is simple and rock solid. I love image backups.
Which brings us to WIN 7's built-in backup. I hate it. Not intuitive, and I don't trust it.
So, here would be my thoughts:
Use Backup Assist or stay with Acronis to back up the ENTIRE computer to your external USB drive. Possibly go with incremental backups and back up to 45 or 50 days. The nice thing about Backup Assist is it gives you many options to set up backups both what type and destination. Plus, when they come out with new versions, you install over the old one, and you are done. No new huge changes and NO new names like Acronis. Plus, you can back up SQL (you can with Acronis as well, but it is much more expensive). By backing up SQL, you can back up AC, every two minutes or whatever, and it takes about 2 to 3 seconds.
Given that incremental backups are fast, you could do a nightly full backup to your NAS.
Here's the good part. If you have a 1TB or larger drive in your computer, you can allow Backup Assist to back up the computer to the internal drive and then copy that backup to your NAS. Best of both worlds. There is nothing faster or more reliable than a hard drive right in your computer. Of course, your computer can completely crash, and you still have your external backups.
The nice thing about separating your data from your OS, is you can decide to just back up the data drive using less space and having faster backups. You can always reinstall the OS if necessary. Some would make a partition just for AC.
Now, for your "modular" backups (you must have billing software), I would back up AC using its own backup either to Carbonite or, better, your external drives. The AC backups in your BACKUP folder in the Amazing Charts folder are very fragile. They are absolutely in the worst place in your office. You lose Amazing Charts folder, and you lose the backups.
Using the AC backup service is OK, but do NOT back up your Imported Items unless you have an upload of something like 50Mbs. Either back up your Imported Items separately or just include it with your Acronis or Backup Assist backups. They will get way too big to back up online. 4GB is already too big. You have to back up the ENTIRE II each night, when you could be doing just incrementals. I used to always use the backup service. For me, I like to be able to access the backup, and you have to contact AC.
Carbonite is good. iBackup is better. You can back up the SQL database using iBackup. It is one of the few where you can.
You mentioned you have not had to use your backups. Make sure that you
1. Backup 2. Check to see that you are actually backing up what you think you are every two weeks or so. 3. Actually make sure you can restore. Not over your OS or data, but to another location to ensure your backups are good.
What do you mean by "opaque archive?"
