Line 6 Amp Heads

- Line6 Spider Guitar Speaker Cabinet (150 Watts, 4x12 in.) $299.95 on www.Zzounds.com
List: $419.99 = the regular maximum price price
Line6 Spider III HD75 Guitar Amplifier Head (75 Watts) = $249.95
Line6 Spider III HD150 Guitar Amplifier Head (2x75 Watts) = $399.95
You can think about taking another amp head like: Marshall MG100HDFX 100 W = $349.95.
Factory comment: is best suited to the Celestion loaded MG412A (angled) and MG412B (straight) 120W 4x12 in. cabinets. Unbelievable tone, feel, and projection come as standard.
So about your cabinet you did well. Amp heads? As you see, the marshall is in between as is the price. If you can afford it, this one is a killer. If you love effects, distortion, that's the one, no floorboard effects needed.
- Line 6 Spider Valve 100HD 100W Guitar Amp Head = $799.99 on www.musiciansfriend.com.
As you see, a 150W should be great, if you perform somewhere, see and compare.
Do you like effects, a lot, look to some AMP HEADS or FLOORBOARDS.
My amps (3) are a
- Marshall Valvestate: price??? I have this one 12 years
- Marshall AS100D Acoustic Combo Amp 100W. I didn't want at all an acoustic 100W. I went for a 50W. I am a very good customer in the 2 major guitar stores, they know me, and what they tell is the truth, I played both, 20 seconds later: 100W I also use this amp a lot for my electrics.
- My TOP AMP: A Fender Cybertwin = hybrid amp, tubes and digital, too much effects, other amps (modeling), this baby blows you far away, just your shoes will be on their place. 2x75W
- EFFECTS: Line 6 PODXT live, I had a digitech (fantastic board) but I wanted the POD so bad that I traded the digirech. Still regret this. In fact all floor boards are less important, see cybertwin.
I hope you are able to choose, I knoww these amps, they rock.

I don' understand what you want, I am from Belgium, so my mother tongue is Dutch.
But about that RACK-MOUNTABLE HEAD.
You have a cabinet = the big BOX with speakers.
I thought that in my answer was written how great they are
- Line6 Spider III HD75 Guitar Amplifier Head (75 Watts) = $249.95
- Line6 Spider III HD150 Guitar Amplifier Head (2x75 Watts) = $399.95
Isn't this the answer? I looked around on the web, this was what I found.
Maybe you can surf to www.line6.com click on PRODUCTS, CLICK ON AMPS, you will find the SPIDER III in all her glory.
There 10 different LINE6 amps.         
- LINE6 CABINET: FEATURES:
    * Slant Cab with 4 – 12† Custom Celestion® Speakers
    * Designed for Spider III HD75 and Spider III HD150

I made it easier, and the next phrase you'll read is about a SPIDER III AMPHEAD
- there are TWO (2) AMPHEADS:
A HD 75 Watt
A HD 150 Watt and this is what they write.
THE SPIDERâ„¢ III delivers detailed amp models based on some of the greatest guitar sounds ever created. To keep these sounds authentic, we kidnapped some of our favourite artists to dial in each amp model.  Now you can rule the stage with the Insane model with its truly massive gain or explore your sensitive side in the studio with the Clean model.  It’s all up to you.
FEATURES:
    * 12 Custom Amp Models from Clean to Insane
    * 7 Smart Control FX (up to 3 simultaneous) including Tape Echo, Sweep Echo, Standard Delay (all with Tap Tempo) Chorus/Flanger, Phaser, Tremolo, and Reverb
    * 250 artist-created presets
    * 150 song-based presets
    * Plus 36 user programmable presets
    * Built-in front panel tuner
    * 150 Watts Stereo (75W x 2)
    * Dimensions: 26.4L x 9.25H x 10.75
I had the impression that my answer and all the extra information was correct.
So if this isn't the answer that I wrote you already + extra information about some other ampheads, also describing what I use, I really don't know WHAT I DID WRONG

Thanks Russell, I just wanted to help (and as you know, I have "BY ACCIDENT" more than time) so as you know, it's a matter of honour to help, and to figure out the best solution. It takes me in at least between 30 and 90 minutes, to surf, search, compare, and posting all this info. As I told some expressions, I never heard of these, but I am a very fast student.
So GREY, I really want to help you (as told I have more than enough time, and it keeps me busy, I'm a Medical Doc, but due to the sequels of a car crash, I am disabled and this keeps me busy). Is it an amphead you want, or what do you mean by RACK-MOUNTABLE HEAD, I was convinced that it was a Line6 amphead. I will try to find out what this means.

I checked the line 6 website   (www.line6.com) and couldn't find any rack mount heads listed...    You might could check with Line 6 and see if the amp heads that they have are removeable from the cabinet and rack mountable...   I've often thought about doing the same...mount an amp and all my effects in one rack unit...   (Old guy...lots of rack stuff accumulated over the years)