What everyone has been driving at is you don't buy either system, you buy individual components. This is the only way to get quality anything. All in one systems have little or no connectivity and a year later when any single component in the system fails the entire system becomes landfill.
So you buy an AVR (Audio Video Receiver), you buy speakers, and you buy a subwoofer. You also buy a Blu-ray player. If all of these components have the same brand name on them you did something wrong. Onkyo for example makes a good receiver but makes horrible speakers. Your Bluray player might be Panasonic, or Pioneer, your speakers might be Emotiva, your sub Polk. You have to find the best product within each category and it's usually a different brand than everything else.
As others have said, ignore the wattage rating unless you are buying dedicated external power amplifiers. (which is the best but also most expensive way). With an HTiB expect it's actual total power to be less than 10% the rating. With a typical AVR even a very expensive one (expensive being defined as > $2,000.00) expect the total to be about 40 ~ 50% of the rating. Only companies like Anthem and NAD rate their receivers properly (all channels driven). The all channels driven rating is typical in separate dedicated amplifiers, even relatively inexpensive ones.
So, Bluray or DVD, definitely Bluray, no brainer on that. Do systems with the same power rating sound the same? No, definitely not. Even if the power ratings were real there is a lot more to it than that. There are so many complexities involved that the industry doesn't even know for certain what all parameters should be measured or what the correct targets should be. There are measurable distortions etc that are very well defined and yet even on these product performance varies dramatically. When it comes to the things no one even understands fully... even more variation. You need to go out and do some listening to systems, there is a very big subjective component to all this.
Video wise you want the BluRay system because it will play both DVD and BluRay disks.
Sound wise - they are actually something like 21 watts per channel. Very weak - but they assume you wont read the fine print on HOW the power was measured to understand the cheats.
You also cannot hook your HDTV sound to the units, cannot hook a game system, etc. They are crappy disk-players and that is all.
When everything is sold together like that they are called home theater in a box or HTiB for short. They are notorious for being proprietary and having inferior sound quality. that doesn't mean they are all bad but you are picking for a needle in a haystack. some of the new F series samsung HTiB's sound really good for a entry level sound system. As was mentioned before do not look at power rating they are are so far off it's crazy.
Help us help you out. What models were you looking at? How much were you planning on spending? There are some fairly inexpensive pre-built systems out there (link) for entry level.