SBS Server: Build check

I'm going to be ordering a new server on Wednesday. I'm torn between two choices. Please give me your thoughts.

Use:
Hyper-V host
1 SBS 2008 VM running Exchange (~20GB data)/Active Directory/Terminal Services/SQL/Symantec Endpoint Server/WSUS/BackupExec
1 Win2k8 server running file & printer sharing (We have 2 high-end Canon MFP--50-75 pages/minute, 3 smaller printers, and about 300-400GB of data)
1 Linux VM for web backups

We have about 30 users & 35 machines using the network every day. All user's have their documents redirected to shares on the server.

Model A (Dell R510):

Intel Xeon E5630 2.53 GHZ
16GB Dual Ranked UDIMMS
Dell H700i RAID controller (512MB cache w/battery)
RAID 10 Array
8x 300GB 10k rpm 2.5" hot-plug drives
Dual 750W PSU
Intel Dual port Gigabit NIC
DRAC Enterprise w/virtual console
sliding rack rails
~$5350

Model B (Dell R515)


2x AMD Opteron 4184 2.8 GHZ Processor
16GB Single Ranked UDIMMS (8x2GB)
Dell H700i RAID controller (512MB cache w/battery)
RAID 10 Array
8x 300GB 10k rpm 2.5" hot-plug drives
Dual 750W PSU
Intel Dual port Gigabit NIC
DRAC Enterprise w/virtual console
sliding rack rails
~$5150

All thoughts are welcome. I was planning on going with Intel until I logged in today and saw a new model with the AMD had launched. I haven't been able to find too many benchmarks comparing the two, but I figure the AMD will give me 12 cores @ 2.8GHZ, while the Xeon offers 4 hyperthreaded cores that can turbo to 2.8GHZ if needed. Suggestions?

I also had to make the choice between dual or single ranked DIMMS (and registered vs. unregistered). Any thoughts on that are helpful.

Finally, I have pretty much decided based on research & prior advice I recieved to go with RAID 10 vs RAID 5/6. I went with 2.5" 10k drives instead of 2.5" 15k drives. The price isn't too much different, but as I understand it, the 2.5" drives are more energy-efficient and even though they spin a bit slower, the random access times won't be too much higher. The system will have 4 open drive slots for future expansion.

Thanks!

The AMD server boards that use ddr3 are limited. IF you go with amd and ddr3, I suggest you buy a spare board now. Intel xeons will offer a better board selection and availability later on if you have any problems.

@o1die: The system will be purchased from Dell and it comes with a 3 year warranty. This includes motherboard replacement if needed, so I'm not too worried about that. Our current server had an electrical issue take out the motherboard and Dell had it replaced within 10 business hours at no cost to us. I'm more interested in performance differences between 1 Intel quad-core w/hyperthreading+turbo and 2 AMD hex-core processors.

@sportsfanboy: The h700i 512Cache w/battery is a $300 addon, but I'm getting 35% off. They offer two more expensive options for internal RAID controllers: H700i w/512 NVDIMM $500, H700i 1GB NVDIMM. I'd be hesitant to buy a third-party card unless I just bought two of them right away in case one dies. The new Dell H200/H700/H800 all offer the ability to migrate the RAID array to any other Dell H200/H700/H800 in case of failure...including moving from an H700 to an H800 or vice versa.