Firstly, it's up to you completely whether you'd prefer a retail or RGH console. We can't make the decision for you.

1- No. Technically not. You can purchase time on a server(like XBLSE) to connect to XBL. This costs $20 per day and you risk having your KV banned. If your KV is banned, you need to purchase another one for $20(average price for an unshared KV).
2- That depends. Do you mean visual modifications? You can RGH a trinity console. You can install the dual nand exploit to a trinity console. This basically means that you have a retail and an RGH , all in one console. With the flick of a switch, you change from retail to RGH nand. This way you can connect to XBL on your retail and then you can modify on your RGH nand. You will still need XBLSE to connect to XBL on the RGH nand however. There are also many visual modifications you can have done if you're interested.
3- That depends. Information on what? XBLSE? Modifying? What information do you need?

If you want to modify games and play emulators, RGH your console. If you want to connect to XBL and play games on LIVE with your friends, keep it retail. If you want both, RGH it and have the dual nand exploit installed to your console.

Wow thanks for the quick reply, can you tell me more about this dual nand setup

cobra0702 wrote Wow thanks for the quick reply, can you tell me more about this dual nand setup

No bother. Apologies I took so long to reply to this, not been on here for a while. If you send me a PM, I'll be able to reply more quickly and easily. Just send me a PM with any questions you have, I'll be sure to answer them.

The dual nand is basically two consoles in one. When your console is RGH'ed, what happens is your consoles nand is modified. To make a long story short, this allows you to run unsigned code and thus modify games, run emulator's and install programs such as FSD and xexmenu. When you perform the dual nand exploit, you have an RGH nand and a retail nand. You can then easily switch from retail to RGH nand by using a button on the back of your console. To have your console RGHed will cost you anywhere between 30 and 50GBP, depending who you have perform the exploit for you and how much shipping is. The dual nand exploit will cost you around 90-100GBP to have someone install it for you. If you're going to perform the exploit(s) yourself, an RGH chip is around 25GBP and a dual nand chip is around 35-40GBP.