3 Super Serums for Dehydrated Skin: from budget to luxury

Do you use a serum? It seems that most people are aware of them nowadays, but not everyone really understands what they can do for their skin, or believe they really need to bother. 
Until I started really investing in my skin in my mid 20s, I wasn't using a serum; now I use a serum twice a day. My skin is definitely looking better in my 30s than it ever did in my 20s; make-up applies better and I have no dry patches despite having dry skin.
These are my top 3 serums at the moment and they come at very different price points.
Serums nourish and treat your skin after cleansing and before moisturising. They can work to add extra hydration and smoothing ingredients that benefit your skin during the day and at night. From my experience, just moisturising is fine, but if you really want to see results and make changes to the uniformity and texture of your skin longer term, serums are a must.
Read on to hear about 3 amazing serums for dry, dehydrated and sensitive skin:

On a budget: La Roche-Posay Hydraphase Intense Serum
With hyaluronic acid and thermal spring water, this light serum is perfect for dehydrated and sensitive skin. Although it retails for £19 usually, you can usually find discounts on this brand. Check out escentual for great brand discounts on a regular basis.
It has a gel/ water-like texture and absorbs quickly, meaning that moisturiser can be applied afterwards. It definitely makes skin more hydrated and sorts out dry patches over the course of a few days. Some hyaluronic products tend to leave skin feeling quite dry (which is normal as moisturiser is intended to be applied on top, sealing in the skin-beneficial products). This serum does not leave skin dry at all, so it is a pleasant experience using it. La Roche-Posay is a reliable brand for sensitive skin from my own experience- check out this post for my take on other L R-P products.
It is similar in consistency and effectiveness to Vichy's Aqualia Thermal Serum which is a tiny bit pricier, but also an amazing serum for dry- dehydrated complexions. I currently do not own this, but I found it to be a beautiful product with great results. I know that Sali Hughes has recommended it on many occasions and I can absolutely see why.

Slightly pricier: Paula's Choice Resist Anti-Ageing Super Antioxidant Serum
At £33 rrp. Paula's Choice is a slightly higher end serum, but one packed with skin beneficial ingredients such as vitamin C which brightens and firms skin. It is for all skin types and feels very silky on application. Another benefit of this product is that it can be applied around the eye area as it is fragrance-free. 
I haven't seen dramatic effects on my pigmentation spots (which this product claims to reduce), but it does feel lovely and makes make-up application really easy. I wear this mostly in the day as it is so easy and doesn't ever feel heavy or greasy.

Pure luxury: Tata Harper Rejuvenating Serum
I got this in a Cult Beauty promotional box and would probably not have tried it otherwise, due to its £80 price tag. Infused with hyaluronic acid, vitamins and antioxidants- this product is 100% natural. The scent is not overpowering and is very pleasant to apply. This amazing serum feels cooling and moisturising every time I apply it in the morning and I have been using it for a good few months every single day under a moisturiser with spf. It is richer and feels more of a powerhouse compared to the serums mentioned above- the name really suits it.
I have noticed that my skin has been more glowy and less dehydrated thanks to this product. Make-up application is also a dream in that I don't have to worry about foundations sticking to drier areas- this really sorts them out. In addition, when I've been using this serum I am so much less self-conscious about my ever-growing fine lines (some of which are down to dehydrated skin; some just come with the '30-something club' membership).
The problem I have is that although I have around two to three months of product left, I will inevitably run out. That day will be a sad one! I am in two minds as to whether I could justify the spend on this serum. Perhaps if I wasn't saving, I would, but I think it would be one for a birthday treat, rather than an everyday purchase. If you have the means to get your hands on Tata Harper's serum, I would whole-heartedly recommend you to because it delivers on its promises and is a joy to use.
Do you have any serum recommendations?