Best way to setup my LAN

I'm struggling to find the best approach here. Here's what I got:

1) Mac Mini 2.0Ghz running Snow Leopard
2) Mac Book Pro 2.53Ghz running Leopard
3) Mac Book 2.0Ghz running Leopard

My wife and I each use a laptop as our regular computer. The Mac Mini we just picked up and are looking to use it as a home server (although it doesn't have Snow Leopard Server).

We use a program for our business called Daylite that hosts a database that we share between laptops - this is being hosted on the Mac Mini, which will always be powered on so we each can access it. There are also a couple folders that we would like to share on the Mac Mini.

This Mac Mini will also sit next to our HDTV to be used for streaming, HULU Netflix, etc..

My problem is that I don't know the best way to configure the Mac Mini on the network.

I have a Verizon Actiontec Router and Comcast Internet (Dynamic IP, although it has been the same for some time).

My questions are:

1) Does it make a difference if I have the Mac Mini directly plugged into the router via ethernet vs wireless? Right now, when we try and File Share between the Mac Mini and laptops, it takes forever to connect, navigate, save files, especially if I am saving to the Mac Mini, from a laptop using Photoshop or even Word.

2) Do I gain anything from running the cable modem directly to the Mac Mini and the enable Internet Sharing from the two laptops, as opposed to using the router?

3) I transferred 1 gig worth of files from a laptop to the Mac Mini and it literally took an hour. I retried it using a direct connection via eithernet between the two computers and it took 10 minutes. I'm hoping that optimizing my setup will speed up my local network transfers. Yes, no?

4) Can I used a Mini DVI to HDMI adapter from my Mac Mini to my tv? If so, does this also send audio signal? It's an Early 2009 Mac Mini.

Thanks for your help!

1) Generally you want stationary machines plugged into the network - into a gigabit port. This will give you maximum access rates into those machines. All my stationary machines are connected through gigabit ethernet. Plus as you move data around - and you have it all wireless - you will run into contention and usage problems if you are moving large files.

2) No this is a poor way to setup wireless. It is insecure and Ad Hoc - as the name suggests. Keep a router.

3) The theoretical limit of 802.11n is 108Mbps - where if you have a gigabit switch the theoretical limit is 1000Mbps - 10x faster so a 10x improvement in time is to be expected. If I am ever moving anything over a gig - I connect to the gigabit lan and transfer it. I also use a control program called flow - that helps keep the connection going.
Flow - Mac OS X FTP and SFTP Client
I used flow to move my 630GB time machine backup from one disk to another.

4) I believe only the latest Mac minis have the proper connection for audio - according to this your early mac mini does not - you'll just have to run an optical cable
How do I connect an Intel Mac mini to a television? @ EveryMac.com