it is definately enough to power them. you dont have to turn your gain all the way up. may be able to find a cheaper one but that is a nice amp and will do the job.

a head unit with multiple pre outs would be best but you can make it work with any head unit.

 

Alright well I have a few ideas for head units. My guess is I'll have to go into a store to really check them out but here are a couple ideas. Clarion CZ301 CD receiver at Crutchfield.com
Here's one of those pioneers that you love so much haha
Pioneer DEH-4300UB CD receiver at Crutchfield.com

Basically I went to crutchfield and selected 4 channel preamp outputs. Is that what you meant by "multiple pre outs?" Also if you have any head units that you're partial too feel free to share. I only need two things, the ability to use an ipod and a cd receiver.

edit: also I forgot to mention that my accord has a six disc cd changer. I would like to keep this but not if it means I can't get a new head unit or it bumps the price up too much. Do you know if that would be compatible with any of these or what I would have to do?

 

here is the next model up of that clarion for 139.99. it has 3 out puts front rear and sub. instead of a front and switchable rear/sub.
Clarion CZ401 (CZ 401) CD/MP3/WMA Receiver w/ HD Radio, USB & Aux
and here is the next step up for 159.99
Clarion CZ501 (CZ-501) Car Stereo CD w/ Bluetooth +iPod USB Cable

here are three levels of pioneer. the one you posted and the next two up.
Pioneer DEH-4300UB CD/MP3/WMA Car Stereo w/ Aux/USB/iPod Controls
Pioneer DEH-6300UB Car Stereo CD/MP3 Receiver with Aux In and USB/iPod
Pioneer DEH-7300BT CD/MP3 Car Stereo w/ Bluetooth, Aux, USB/iPod


it doesnt appear that either will take the the disc changer. my preference of all of those would be the 6300ub. I like the fact that it has the 5 band eq. That is what my father has in his truck and it is really nice.

 

Wow. You two have been busy.

The KTP-445 is a nice piece. Simple and easy to install. Better power than an HU without the hassle of an amp.

That said, an external amp is going to offer better power. I like matching brands, so if you find a Kicker sub amp you like, get a Kicker 4 channel.

I like Crutchfield. You get a warranty, install accessories for free, and excellent customer service. Probably the best place to shop for car audio, period. Prices are MAP and fair for authorized sellers.

 

The CDE-121 only has two preouts. With that HU, the KTP-445 is a better bet. If you want a external amp for front and rear speakers, and a sub, you want a HU with six preouts.

Look at Kenwood eXcelon for a great HU with more features and better outputs.

 

Haha welcome back KHA. I appreciate all the help from you two btw. So if I get everything from a different brand is that bad? I assume that things from the same brand tend to work together better? I know that my dad has pretty much diamond everything in his accord. (three accords in my family btw mine, my dad's, and my sisters) Let’s recap… this is what neophyte and I have kind of “decided” so far.
Head Unit: undecided (possibly the Excelon KDC-X395)
Speakers: Boston Acoustics SE65RC 6-1/2" 2-way car speakers at Crutchfield.com and Boston Acoustics SE95 6"x9" 2-way car speakers at Crutchfield.com (already installed)
Amp(s): Kicker ZX500.1 (10ZX500.1) Class D Mono Amplifier Car Amp (possibly this for the sub)
Rockford Fosgate R300-4 (r3004) 300W, Prime Series 4-Channel (and this for the speakers) buuut I’m open to cheaper suggestions that maintain quality 
Sub: Alpine SWR-1243D (SWR1243D) 12" Dual 4 ohm Type-R Car Subwoofer

All of these are open for suggestions except for the speakers. I really wish that my dad could’ve let me help decide which speakers to get but I’m not complaining since they’re free! Also just a side note, I will probably be purchasing a head unit and amp very soon but, but, due to budget issues, I won’t be able to buy the sub and mono block until I get paid a couple more times

 

Your plan sounds fine, no issues with various brands as long as you maintain impedance ratings/loads.