First off thank you miltestpilot! Ok I looked just to make sure and there is plenty of room between the back of the PS and the back of my CD drive. I am thinking the Silencer 470 looks good but if you look at the Dell list the Silencer is not on the 4600, it calls for the Silencer Dell-2? I am confused on this issue. It looks as if they have the same connectors and such but different power outputs. I also noticed the Dell-2 is +12V @ 23A and the 470 is +12V @ 26A and they also have an amp difference in current ratings. Maybe I am looking into this too deep I just don't want to end up with a power supply I can't use. Thanks for all the help!
What you are reading is what makes one PSU better than the other. You can have 100A on the 12v. 3.3v and 5v and its not going to hurt the system, just give it more power to work with and what ever it does not use the PSU just runs cooler and more efficient.
I said in my post to not use the one PC Power posted for your tower because you need something a bit stronger for the video card you intend to run and leave enough left over to run quiet and cool. The Dell Silencer 470 is the one you want and it will even leave a bit of room for things like a memory upgrade too. If you think you may keep that tower and upgrade the video card again later, like to a 7800 or a 7950 you should get the 610 PSU which will run everything you have and those faster cards too.
The plugs, the box size and the mounts are the same for the Dell-1, Dell-2 and the top end Dell replacement which is the Silencer 470.
There is no such thing as too much, only too little.