I like Kicker speakers a lot. Kicker makes a very good speaker. You can buy them at Crutchfield. A Google search will probably turn up a $20.00 off coupon and Crutchfield has free shipping right now. You could do a set of components up front and coaxials in the rear to save a bit on the price, and you won't have any negative aspects in the sound quality. Really the best way to select a speaker is to audition it for yourself in the store with music you prefer on CD or a thumb drive. When I bought my 2 pairs of Kicker KS62 coaxials I listened to them in a Best Buy store. I had a thumb drive with music I like on it. Best Buy sells the KS 62 for about $99.00/pair. Crutchfield had them at $75.00/pair with free shipping. Best Buy will not match an online price so I bought from Crutchfield, 2 pairs of KS 62's cost me $130.00 shipped after I used a $20.00 Crutchfield coupon from
www.retailmenot.com.
Focal makes good speakers. So does JL. So do a lot of other manufacturers. You just have to listen to different speakers and get the ones that sound best to you that are within your budget. If you buy from Crutchfield they give you free speaker mounting adapter plates and free speaker wire harness plug connectors that will take the guesswork out of identifying the factory speaker wire polarity. Best Buy often runs free installation deals too. Their installers are usually very talented and conscientious. I should know, I used to be one myself but that was long ago, way before anyone ever heard of the Geek Squad.
Kicker also makes very good amplifiers, good clean strong power for a pretty good price. Best Buy sells Kicker amps too, and so does Crutchfield but for some reason Crutchfield does not sell any Kicker 4 channel amps.
www.sonicelectronix.com does and I think they even include or offer a discount on the amplifier wiring kits. Sonic Electronix has great prices as well. I use an old Kicker KX350 amp in my system and it does a great job, sounds good both at low and high volume.
You can use a good 4 channel amp, use the front outputs for the front and rear full range speakers and use the rear channels bridged for your subwoofer. Personally I do not care for powered subs, especially in the trunk. A regular sub in a sealed enclosure with a good strong amp on it will sound better and may even cost less. Kicker and Alpine both make good subs that won't break the bank or require a monster sized enclosure. Again, with subs you need to audition them in the store. If a sub or full range speaker sounds good to you in the store, it should also sound good in your car.
If you don't want to do the installation yourself, you can try Best Buy or you may get better workmanship and customer service at a good local independent car audio store. Their prices may be higher, though. Best thing to do there is ask around and someone you know may know of a good shop. Crutchfield has a great staff of knowledgeable folks who can help you both with the purchase and any technical problems after the installation is done. I think they used to offer a Crutchfield preferred installer service where they refer you to a Crutchfield-approved car audio installer in your area. I have no idea if they still do that.