Brought a dud DVD recorder.... What are my rights?

I work for a home a/v and appliance store, and we take care of all our customers with most equipment having a factory warranty of a year or more. I think you're only choice is getting it repaired again. About the only other option is if it's a store that can look at their cost on product, not a big-box store like Wal-Mart, is if they will give you a killer deal on a new unit. We usually will give a customer a discount barely above cost on a new item for not meeting their expectations with their first purchase so we can keep them as a returning customer. But you're pretty much hosed on the deal. Otherwise you could always mail someone at the company.

My brother and I had the speakers on each of our radar detectors blow out. I had to mail a letter to a company on something I was dissatisfied or happy with. I decided to send them a letter explaining what happened and what I wanted them to do. They shipped two speakers back for me to replace (easy 2 minute job). You could mail them a letter including your model and serial number, along with a copy of your receipt and explain what has been happening asking them to fix or replace your unit. That's your best bet. This may be the information you need to contact them:

Philips Electronics North America
3000 Minuteman Road
M/S 109
Andover, MA 01810
(800) 223-1828

If still under warranty, it pretty much does not offer replacement, but only repair.

I do believe in being polite but firm. Pursue customer service. For me it yielded the number to executive customer service. Once there I submitted documentation of repeated repair. In fact, twice because they lost track of the first submission (lost terminally in someone's in box. Eventually, some supervisor was having a good day & reimbursed me for most of the repair cost.

Polite but firm also sort of means being a pest by not going away.

A lot of these people are utter crooks, from the manufacturer to the retailer. Nobody really cares about your satisfaction, rights etc.
First I would return to the store and demand a refund. If I didn't get it, I would be real loud and vocal with them about the problem so other shoppers can hear it. Give them some bad publicity, then take your business elaswhere.