Yes, You do still get all the mods and everything available to download, they just take your licence after one year. If you upgrade in the first few days it cheaper from the year to full.
With a leased license, you do get the mods / access to vbulletin.org for 1 year... as mentioned above. Here is another thing to consider however... You CAN NOT sell / transfer a leased license. If you go with the owned license and things don't work out, you can sell it and recoup some of your money back (about $110 - $130.00). You must sell after 90 days of ownership and while there is still support. So if you own it longer than a year and the support portion of the owned license runs out, you would have to renew it before selling it. You should know if you are going to continue to use it within a year.
I personally go with leased. If I start a forum and it manages to last a year then I wouldn't mind spending the extra cash to upgrade to an owned license. However, If I start a forum and it bombs then I've only lost 50% of what I would have. Most owned licenses go for around $100, so it's really not much of a difference between getting a leased and just letting it expire and getting an owned and selling it when you decide to quit.
Also, I think there's a couple month grace period when you can upgrade your leased license to an owned license for just the remainder of the cost (ie ~$80). So it's a win win I think.