The steed stone is very useful but i tend to use the lord stone more often.

You shouldn't need to... If you're a mage, the biggest threat is probably other mages, with the occasional archer. Mages are easy enough - Enchant some gear to resist magicka and the elements. As for archers, never underestimate the power of a good distraction. This is why I have conjuration on my mainly destruction mage - an Atronoch makes for a very good destraction! Lure their arrows away, pop in, throw a few shots, and you're done.

Your only real threat are thigns which resist all elements, which even then, you still have conjuration for! Summoning stuff as well as bound gear will really help you in such rare binds.

If you want to take advantage of the alteration fleshspell perks

Only reason for robes is roleplaying looks and carrying capacity. You can perk out the weight of your worn armor eventually, but if you have more than one set I dont think the perk covers it.

Another question is: Are you playing modded or unmodded.

Vanilla: There is no major advantage to not wearing armor. Wearing armor provides you more protection against physical damage, but you might need to invest in some armor perks to really make it count, which would take away from the points you can put in Magicka based skills. Another thing to consider though: The archmage in Oblivion wore heavy armor, and looked awesome.

Modded: If you get some of the magicka rebalance mods, you can get bonuses to your Oakflesh or wards when casting spells sans armor.

Alteration's Mage armour to rank 3 with the Eboneyflesh spell, gives you a 300 armour rating.

Whether a mage should wear armor or not seems to be mostly a roleplaying choice since you make a good build either way and there doesn't seem to be much penalty for wearing armor other than the mage armor perk.

But you should know that the mages robes with the dual enchantments of reduced casting cost and increased magicka regen cannot be duplicated on armor with the Enchant skill because the base increase regen rate is only 10%, so you can buy master level robes that reduce casting cost of a particular school AND increase magicka regen rate by 150%. You cannot put this enchantment on armor because when you disenchant such robes, the base rate for increased magicka regen will only be 10%. Even if you use the 100 Enchant perk to dual enchant a reduced casting cost and increased magicka regen, the base for increased magicka regen is only 20%. So, you will never get anywhere near 150% increased magicka regen on armor (without seriously exploiting the alchemy/enchant loop).

This is another potential advantage of robes over armor. However, if you max out Enchant, you can get free casting in two schools, which may reneder an increased magicka regen rate somewhat moot, so in the end it is mostly a roleplaying choice.

Well, personally, I never train skills. Without that, my mage would never ever level an armor skill. Getting hit enough to level up an armor skill means I would have been killed multiple times in one-shots. Mages to me are best kept in cloth for maximum speed. There are spells that act as armor if you need, but dodging out of the way is really your best defense.

That's good information to have, thanks for that! I'm not a hardcoe RP'er, though I prefer the idea of an unarmed and unarmored mage melting faces!

Another question, the Alteration perk Mage Armor improves the "Flesh" spells when not wearing armor. Does this mean no armor in any slot (head, hand, chest or feet) or just the chest piece? Because I'm pretty fond of the Morokei (sp?) dragon priest mask at the moment....

Any armor in the head, chest, shin or hand slot will break the mage armor perk. The dragon priest masks all break the effect unfortunately .

You can use a shield though , or become a werewolf as they are technically without armor.

I tried out Glass Armor and became much tougher, even with low skill in light armor. 100 Enchant allows you to attach at least two Fortify Light armor buffs, each providing somewhere around 43% increase.

You will skill up fairly rapidly once you realise you're more of a tank, get sloppy with your spellcasting and start taking a lot of hits.

Since there is no penalty then there really isn't a reason why a mage should't wear armor.

Unfortunately this is the case, I do hope the give mages more of a incentive to wear robes. I do anyway as its more fun, more suitable to me.

Except that if you look at the perks closely, you can be pretty selective about the perks you take for each skill. Not every perk in a tree will necessarily be useful to you. In particular, avoid the mage armor perks in alteration if you're going to use light or heavy and don't invest unnecessarily in mana cost reduction perks if you plan majorly to reduce those costs via enchants. Personally, I've not perked frost or taken the finishers in the destruction tree and don't plan to perk elemental damage with enchants. If you're choosy, you can afford to perk additional skills.

Skyrim is beyond class, really, even moreso than Oblivion was. By definition, all PCs are custom classes. SOOOOO... do what you want, what you feel comfortable with and play your character however you like. There's no class hand-holding, restriction penalties, etc. It would, however, be pointless to wear armor and invest heavily in Alteration armors, it just wouldn't make sense for the PC or the player.

you won't put a 150% magicka regen on anything. At least I haven't been able to even with potions to improve enchant.

I haven't played around with it much, but I know I can enchant at least 50% regen on my dragonplate armor.