SQL 2005 Setup Configuration

I'm a Network Administrator that has to do everything from desktop to server, to routing, and DBA so I need a bit of advice. Stretched thin for time and knowledge in the SQL area and trying to do the best I can.

I currently have a MS SQL 2000 database that is 60GB in size for MS Dynamics 8.0 and one that is 2GB that I want to move to a new server.

I've setup and tested it and it all works, now I'm looking for some Best Practices information for best performance. Currently doing about 3,000 transactions a day.

Server is HP ML350-G5 2 Xeon Dual Core 2.0GHz CPUs w/16GB RAM w/external drive bays running 72GB 15K SAS drives with SMART ARRAY P800.
OS is Windows Server 2003 Enterprise w/SP2 - MS SQL 2005 Standard
I have the following drive configurations setup.

C:(RAID1+0)OS - SQL 2005
D:(RAID1+0)Dynamics Application Shared dictionary files for clients
G:(RAID0)BACKUPS (see note below about TEMPDB) I also have a 25GB swap file on this drive maybe better to put in on the D: volume if I put TEMPDB here
H:(RAID1+0)LOGS (2 user db logs and the tempdb log)
I:(RAID1+0)DATA (2 user db - [model, msdb, master]

Recently found that my G: drive (RAID0) only has space for 2 backups (poor space planning on my part) before I need to move the files. Normally I backup the DB with BackupExec 10.1d just fine in about 2 hours over the wire at night since no one is in the DB at night.
Was wondering if putting my TEMPDB there on (RAID0) would be advisable or not. In SQL 2005 it gets rebuilt each time SQL is restarted so it would seem that ensuring it's on a RAID1 or RAID1+0 might not be as necessary as say the DATA files.
Then if I really wanted to I could actually do backups on the I:DATA drive at night and then use TAPE to back that up, and use an automated script to move them off to offline storage once the TAPE backup is done.

For the [model, msdb, master] should they need to be on the I:DATA drive or just leave them on C:OS ? Not sure how much they're actually used.

Also doing some brief testing the Microsoft Dynamics was much slower on the new Server than it was on the original. Odd to me since the new Server is like a McLaren F1 racing a Ford Pinto. The old server is running a single P4 CPU and 6GB RAM

I've set MS SQL 2005 to use 12GB of RAM on the new server so as to leave 4GB for other Server tasks.

I ran the Maintenance Wizard and had it do checks and defrag and index rebuild etc... so not really sure why the speed would be noticeably slower. One thing I did notice is that once a screen query was ran then the next time it was a bit faster but overall I was expecting to see the screens fly by on this new hardware and SQL 2005 but it doesn't really do that.

I've read some of the white papers etc for tuning, but wow I just don't have unlimited hours to do all this analysis, there seem to be hundreds of pages to read on that type of stuff.

Thanks in advance for the advice.