1. Subdomains can be useful to some people and in certain situations if you intend running subsections of a site - kind of a site within a site - but it can also become horribly confusing to newcomers and I shouldn't think that this would be a top of the list of features you could look out for.
2. Meta Tags are still useful, but these days search engines 'read' a page text the same (more or less) as a site visitor would, so good, clear, concise and relevant explanitory text is king to getting indexed, as long as you take the trouble to register the domain with the major engines to begin with. Doing this manually takes a while but has obvious payoffs when things start rolling, but this process can take several months so don't expect overnight results. Including the URL on all literature - business cards, letterheads, flyers and similar is still probably the best way to get your site hits without spending a fortune.
3. Updating the site should not be a chore. Some hosts use slightly bizarre and even confusing web folder directory structures which does not help your situation. You can upload direct from Dreamweaver without the need for a third party FTP program but although it can get you up and running it is not as useful as it may first sound due to certain limitations of the program. It does the job though.
Hosting is a minefield and if you ask 100 web designers who to go with you'll get as many replies. Linux hosting is the least expensive and most commonly available to the home and small business user.
Most hosts supply petty straight forward destructions on how to upload and configure your FTP account, but some of them seem to insist on you using an FTP client of their choice which may not necessarily be yours.
In general, once your account is set up with the FTP program you prefer all you do is go online, launch your FTP program, double click the account to access your web folder serverside (assuming you set your FTP client up to remember your account username and password). Then you browse to your local web folder on your PC and select which files to transfer. Some people find overwriting files without deleting the originals on their web host folder can cause problems, but this is normally a local issue to do with your system.
There has been much talk of hosting in other threads in the WebDesign forum and a quick look at some of them will give you more links than you can shake a stick at. Pricing varies wildly and so, unfortunately, does quality of service. For a home or small business package you should be able to find something with all the features you need for well under a hundred pounds per year. If you shop around you can find hosting for half of that, but it is not for me or anyone else to tell you which way to go with this.
Useful links for you could include:
Areti at click here (Forum Editors personal favourite).
2020 Media at click here
Easily at click here
WebFusion at click here
HostWay (sponsors of this forum) at click here
And don't forget 1&1, although personally I find their account management system unnecessarily complicated to newbies.
I'd suggest you come back to us with specific areas of confusion and one of us will try and walk you through things.
One point you should never overlook; talk to your intended host. All of the hosting companies above will speak with you on the telephone and advise on how to go about setting your account up, which account most suitably meets your requirements and so on. Don't ever feel that you are out of line by calling and asking for help; it's part of what you are paying for.